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Lease - AVEO PHARMACEUTICALS INC - 5-9-2012

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					                                       Exhibit 10.3

              LEASE

          by and between

   BMR-650 E KENDALL B LLC,
a Delaware limited liability company

                and

AVEO PHARMACEUTICALS, INC.,
    a Delaware corporation
                                                 TABLE OF CONTENTS
  
                                                                               Page  

1.        Lease of Premises                                                        1  
2.        Basic Lease Provisions                                                   2  
3.        Term                                                                     5  
4.        Possession and Commencement Date                                         5  
5.        Condition of Premises                                                    7  
6.        Rentable Area                                                            7  
7.        Rent                                                                     7  
8.        Rent Adjustments                                                         8  
9.        Operating Expenses                                                       8  
10.    Taxes on Tenant’s Property                                                  13  
11.    Security Deposit                                                            14  
12.    Use                                                                         15  
13.    Rules and Regulations, CC&Rs, Parking Facilities and Common Areas           18  
14.    Property Control by Landlord                                                21  
15.    Quiet Enjoyment                                                             22  
16.    Utilities and Services                                                      22  
17.    Alterations                                                                 25  
18.    Repairs and Maintenance                                                     28  
19.    Liens                                                                       30  
20.    Estoppel Certificate                                                        31  
21.    Hazardous Materials                                                         32  
22.    Odors and Exhaust                                                           35  
23.    Insurance; Waiver of Subrogation                                            36  
24.    Damage or Destruction                                                       38  
25.    Eminent Domain                                                              41  
26.    Surrender                                                                   42  
27.    Holding Over                                                                42  
28.    Indemnification and Exculpation                                             43  
29.    Assignment or Subletting                                                    44  
30.    Subordination and Attornment                                                48  
31.    Defaults and Remedies                                                       49  
  
                                                             i
                                       TABLE OF CONTENTS
                                           (continued)
  
                                                               Page  

32.    Bankruptcy                                                  53  
33.    Brokers                                                     54  
34.    Definition of Landlord                                      54  
35.    Limitation of Liability                                     55  
36.    Joint and Several Obligations                               56  
37.    Representations                                             56  
38.    Confidentiality                                             57  
39.    Notices                                                     57  
40.    Rooftop Installation Area                                   57  
41.    Miscellaneous                                               59  
42.    Options to Extend Term                                      61  
43.    Right of First Offer                                        62  
44.    Right of First Refusal                                      64  
  
                                               ii
                                TABLE OF DEFINITIONS
  
                                                                   Page  

Accountant                                                            12  
ADA                                                                   17  
Additional Rent                                                        7  
Affected Areas                                                        38  
Alterations                                                           25  
ANSI                                                                  42  
Applicable Laws                                           3, 5, 8, 9, 10  
Available ROFO Premises                                               63  
Available ROFR Premises                                               64  
Bankruptcy Code                                                       50  
Base Rent                                                              3  
Baseball Arbitrator                                                   61  
BMBL                                                                  33  
Broker                                                                54  
Building                                                               1  
CC&R                                                                  18  
Claims                                                                17  
Common Area                                                            1  
Cosmetic Alterations                                                  26  
Damage Repair Estimate                                                39  
Default                                                               49  
Default Rate                                                          49  
DHHS                                                                  33  
Discount Rate                                                         51  
Execution Date                                                         1  
Exempt Transfers                                                      44  
Existing Mortgagee                                                    48  
Exit Survey                                                           42  
FMV                                                                   61  
Garage                                                                20  
Garage Operator                                                       20  
Garage Parking Spaces                                                 20  
Generator                                                             24  
Governmental Authority                                                 8  
Hazardous Material                                                    32  
Hazardous Materials Documents                                         33  
HVAC                                                                   5  
Independent Review                                                    11  
L/C Security                                                          14  
Land                                                                   1  
Landlord                                                           1, 54  
Landlord Delay                                                         6  
Landlord Indemnitees                                                  17  
Landlord Parties                                                      37  
  
                                         iii
                                          TABLE OF DEFINITIONS
                                               (continued)
  
                                                                      Page  

Lease                                                                      1  
Lender                                                                    17  
Mortgagee                                                                 48  
MWRA                                                                      18  
New Tenant                                                                35  
Notice of Marketing                                                       63  
Notice of Offer                                                           64  
OFAC                                                                      56  
Operating Expenses                                                         8  
Option                                                                    61  
Option Notice                                                             61  
Phase 1 Premises                                                           5  
Phase 1 Premises Deadline                                                  5  
Phase 1 Premises Rent Commencement Date                                    5  
Phase 1 Premises Tenant Improvements                                       5  
Phase 2 Premises                                                           5  
Phase 2 Premises Rent Commencement Date                                    5  
Phase 2 Premises Tenant Improvements                                       5  
Premises                                                                   1  
Property                                                                   1  
Property Management Fee                                                   11  
Property Operations Agreements                                            18  
REBA                                                                      61  
REFA                                                                      61  
Revenue Code                                                              45  
ROFO                                                                      63  
ROFR                                                                      64  
Rooftop Installation Area                                                 57  
Rules and Regulations                                                     18  
Security Deposit                                                          14  
Signage                                                                   16  
SNDA                                                                      48  
Specialty Alterations                                                     27  
Substantial Completion                                                     6  
Substantially Complete                                                     6  
Tenant                                                                     1  
Tenant Improvements                                                        6  
Tenant Premises Notice                                                     2  
Tenant’s Affiliate                                                        44  
Tenant’s Parking Spaces                                                   19  
Tenant’s Rooftop Equipment                                                58  
Tenant’s Share                                                            10  
Term                                                                       5  
Term Expiration Date                                                       5  
Termination Notice                                                        39  
  
                                                   iv
                  TABLE OF DEFINITIONS
                       (continued)
  
                                              Page  

TI Allowance                                       6  
TI Deadline                                        6  
Transfer                                          44  
Transfer Date                                     44  
Transfer Notice                                   44  
UBC                                               34  
Work Letter                                        6  
  
                           v
                                                                LEASE

     THIS LEASE (this “ Lease ”) is entered into as of this 9th day of May, 2012 (the “ Execution Date ”), by and between BMR-
650 E Kendall B LLC, a Delaware limited liability company (“ Landlord ”), and AVEO Pharmaceuticals, Inc., a Delaware
corporation (“ Tenant ”).


                                                              RECITALS

     A. WHEREAS, Landlord owns certain real property commonly known as Parcel B and described further on Exhibit A-1
attached hereto (the “ Land ”) and the improvements on the Property located at 650 East Kendall Street, Cambridge,
Massachusetts, including the building and the Garage (as defined in Section 13.5) (collectively, the “Building”) in which the
Premises (as defined below) are located; and

     B. WHEREAS, Landlord wishes to lease to Tenant, and Tenant desires to lease from Landlord, certain premises (the “ 
Premises ”) located on a portion of the fourth (4th) floor, and the entire fifth (5th) and sixth (6th) floors, together with certain off-
floor mechanical areas, of the Building, pursuant to the terms and conditions of this Lease, as detailed below.

                                                            AGREEMENT

     NOW, THEREFORE, Landlord and Tenant, in consideration of the mutual promises contained herein and for other good
and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and intending to be legally bound,
agree as follows:

1. Lease of Premises .
      1.1. Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord, the Premises, as shown on Exhibit A
attached hereto for use by Tenant in accordance with the Permitted Use (as defined below) and no other uses. The Building,
Land and all landscaping, parking facilities, private drives and other improvements and appurtenances located thereon and
related thereto, including the Building and other buildings located on the Land, are hereinafter collectively referred to as the “ 
Property .” All portions of the Building and Property that are for the non-exclusive use of the tenants of the Property, such as
service corridors, elevators, loading docks, public restrooms, public entranceways, lobbies and stairways, electric and
telephone closets (other than those exclusively serving the Premises, if any), janitor closets, and other areas from time to time
designated as common areas by Landlord (all to the extent located in the Building or on the Property) are hereinafter referred to
as “ Common Area .” The Premises exclude Common Areas, fan rooms, mechanical rooms, elevators wells, pipes, ducts,
conduits, wires and appurtenant fixtures serving other parts of the Property (exclusively or in common), and any exterior walls
(including without limitation the roof and roof system) and structural members of the Building. If the Premises include less than
the entire rentable area of any floor, then the Premises also exclude the common corridors, elevator lobby and toilets located on
such floor.
      Tenant shall have the right, on or before to June 1, 2012, in each case by written notice (a “ Tenant Premises Notice ”) to
Landlord identifying the alternative demising of the Premises proposed by Tenant, to (x) reduce or expand the portion of the 
Premises located on the fourth floor by adjusting the location of the demising walls between the Premises and contiguous
leaseable areas on the fourth floor by an amount not to exceed five thousand (5,000) square feet of Rentable Area, provided that 
the remainder of the leaseable areas on the fourth floor are readily leaseable for multi-tenant purposes in a first class office and
laboratory building, as reasonably determined by Landlord; there is no adverse impact on Building systems or structure as a
result of such adjustment; and/or (y) substitute alternative, existing off-floor mechanical locations in the Building for the off-
floor mechanical portions of the Premises, provided that such areas are, in Landlord’s reasonable determination, of an
equivalent aggregate Rentable Area, do not impose an inequitable allocation or use of similar mechanical spaces for tenant
spaces in the Building, do not reduce any leaseable areas of the Building, and do not adversely affect Building operations or
access. Within 10 days following the giving of a Tenant Premises Notice, Landlord shall approve the proposed revised Premises
or disapprove such proposal with specific reasons therefor. Landlord’s failure to respond within such ten day period shall be
deemed approval by Landlord. Following the adjustment of the Premises in accordance with this Section, the parties shall enter
into an amendment to this Lease substituting the revised Premises plans for the applicable floors of the Premises for the
Premises plans initially attached as Exhibit A hereto, and the annual Base Rent, Tenant’s Parking Spaces, and Tenant’s Pro Rata
Share (as each term is defined below) shall be adjusted accordingly based on the change in Rentable Area of the Premises as
determined by Landlord in accordance with Article 6, below.

2. Basic Lease Provisions . For convenience of the parties, certain basic provisions of this Lease are set forth herein. The
provisions set forth herein are subject to the remaining terms and conditions of this Lease and are to be interpreted in light of
such remaining terms and conditions.

     2.1. This Lease shall take effect upon the Execution Date and, except as specifically otherwise provided within this Lease,
each of the provisions hereof shall be binding upon and inure to the benefit of Landlord and Tenant from the date of execution
and delivery hereof by all parties hereto.

    2.2. In the definitions below, each current Rentable Area (as defined below) is expressed in rentable square footage.
Rentable Areas and “ Tenant’s Pro Rata Shares ” are all subject to adjustment only as expressly provided in this Lease.
  
                                                                             Means the Following (As of the
                     Definition or Provision                                       Execution Date)
                     Rentable Area of Premises                                  126,065 square feet
                     Rentable Area of Building                                  291,498 square feet
                     Rentable Area of Lab Building                              278,736 square feet
                     Tenant’s Pro Rata Share of Building                             43.25%
                     Tenant’s Pro Rata Share of Lab Building                         45.23%
  
                                                                 2
   2.3. Initial monthly and annual installments of Base Rent for the Premises (“ Base Rent ”) as of the Phase 1 Premises Rent
Commencement Date (as defined in Section 4.1 below), subject to adjustment under this Lease:
  
                                                                                          Base Rent per 
                                                                 Square Feet of           Square Foot of 
                                                                 Rentable Area           Rentable Area of      Monthly Base          Annual Base
Dates                                                           for the Premises           the Premises           Rent                  Rent       
Phase 1 Premises Rent Commencement Date – the date                        126,065        $54.50 annually         $572,545.21        $6,870,542.50  
  immediately preceding the first (1 st ) anniversary of
  the Phase 1 Premises Rent Commencement Date                                                                                    

     As further described in Section 4.1, below, Base Rent shall be prorated for the Premises between the Phase 1 and Phase 2 
Premises, and only payable with respect to the Phase 1 Premises, until such time as the Phase 2 Premises Rent Commencement
Date occurs.

     2.4. Term Commencement Date: The date upon which Landlord delivers the Premises to Tenant in its “as is” condition as
of the date hereof with a temporary demising wall constructed on the 4th floor of the Building that is reasonably sufficient for
Tenant to secure such portion of the Premises, which date Landlord shall cause to occur no later than May 31, 2012. 

        2.5. Estimated Term Expiration Date: December 31, 2024. 

        2.6. Security Deposit: $2,862,726.

     2.7. Permitted Use: Office and laboratory use in conformity with all federal, state, municipal and local laws, codes,
ordinances, rules and regulations of Governmental Authorities (as defined below), committees, associations, or other regulatory
committees, agencies or governing bodies having jurisdiction over the Premises, the Building, the Property, Landlord or Tenant,
including both statutory and common law and hazardous waste rules and regulations (“ Applicable Laws ”). Tenant shall obtain
validation by any medical review board or other similar governmental licensing of the Premises required for the Permitted Use.
  
                                                                      3
     2.8. Address for Rent Payment:                BMR-650 E Kendall B LLC

                                                   Pursuant   to the following wire instructions:
                                                   Name of beneficiary: BMR-650 E Kendall B LLC
                                                   Account number: 153495105154
                                                   Bank Name: US Bank
                                                   Routing/Transit #: 122235821
                                                   Branch Name & Address: San Diego Main
                                                   600 W Broadway #100
                                                   San Diego, CA 92101

     2.9. Address for Notices to Landlord:         BMR-650 E Kendall B LLC

                                                   17190 Bernardo Center Drive
                                                   San Diego, California 92128
                                                   Attn: Vice President, Real Estate   Counsel
     2.10. Address for Notices to Tenant:          

     Prior to the Rent Commencement Date:          AVEO Pharmaceuticals, Inc.
                                                   75 Sidney Street
                                                   Cambridge, MA 02139
                                                   Attn: Chief Financial Officer

     On or after the Rent Commencement Date:      At the Premises
     With a copy to:                               Langer & McLaughlin,     LLP
                                                   855 Boylston Street
                                                   Boston, MA 02116


     2.11. The following Exhibits are attached hereto and incorporated herein by reference:
  
            Exhibit A        Premises
            Exhibit A-1      Land
            Exhibit B        Work Letter
            Exhibit B-1       Scope of Landlord’s Demising Work
            Exhibit C        Acknowledgement of Rent Commencement      Date and Term Expiration Date
            Exhibit D        Development Approvals
            Exhibit E        Form of Letter of Credit
            Exhibit F        Rules and Regulations
            Exhibit G        Tenant’s Personal Property
            Exhibit H        Form of Estoppel Certificate
            Exhibit I        SNDA
            Exhibit J        Rooftop Installation Area
            Exhibit K        Kendall Square
            Exhibit L        Tenant’s Signage Location
  
                                                      4
3. Term . The actual term of this Lease (as the same may be extended pursuant to Article 42 hereof, and as the same may be
earlier terminated in accordance with this Lease, the “ Term ”) shall commence on the Term Commencement Date and end on the
date that is twelve (12) years after the actual Phase 1 Premises Rent Commencement Date (such date, the “ Term Expiration Date
”), subject to earlier termination of this Lease as provided herein, provided that if the Phase 1 Premises Rent Commencement
Date is not the first day of a calendar month, then the Term Expiration Date shall be the last day of the calendar month in which
the twelfth (12 th ) anniversary of the Phase 1 Premises Rent Commencement Date occurs. 

4. Possession and Commencement Date .
      4.1. Landlord has delivered to Tenant, broom clean and free of occupants, and Tenant has accepted possession of, the
Premises as of the date hereof. Landlord represents and warrants to Tenant that, as of the date hereof, the heating, ventilation
and air-conditioning (“HVAC”), electrical, life safety and plumbing systems of the Building are in good working condition and,
to the best of Landlord’s knowledge, not in violation of Applicable Laws applicable to office and laboratory use, generally.
Tenant shall undertake its Tenant Improvements and occupy the Premises for the conduct of its business in two phases. The “ 
Phase 1 Premises ” shall consist of not less than twenty thousand (20,000) square feet of Rentable Area on the sixth (6th) floor 
of the Building identified by Tenant to Landlord no later than June 1, 2012 (the “ Phase 1 Premises Deadline ”). If Tenant fails to
provide Landlord with such notice by the Phase 1 Premises Deadline, then the Phase 1 Premises shall be as shown on Exhibit B-
2 attached hereto. Promptly following the Phase 1 Premises Deadline, the parties shall enter into a written instrument confirming
the square footage of Rentable Area of the Phase 1 Premises. The “ Phase 2 Premises ” shall consist of the balance of the
Premises. The Rent Commencement Date shall be determined separately for each Phase and Base Rent shall be prorated based
on the ratio of square footage of the Phase 1 Premises to the entire Premises until such time as the “Rent Commencement Date” 
occurs with respect to the entire Premises (i.e., until such time as the Phase 2 Premises Rent Commencement Date occurs). The “ 
Phase 1 Premises Rent Commencement Date ” shall be the earlier of (a) the Date earlier to occur of (i) Substantial Completion of 
the work described on Exhibit B with respect to the Phase 1 Premises (the “ Phase 1 Premises Tenant Improvements ”), and
(ii) January 1, 2013 and (b) the date on which Tenant has occupied any portion of the Phase 1 Premises for the conduct of its 
business, as opposed to occupying any portion of the Phase 1 Premises for the installation of the Tenant Improvements (as
defined below). The “ Phase 2 Premises Rent Commencement Date ” shall be the earlier of (y) the Date that is the earlier to occur 
of (i) Substantial Completion of the work described on Exhibit B with respect to the Phase 2 Premises (the “ Phase 2 Premises
Tenant Improvements ” and, together with the Phase 1 Premises Tenant Improvements, the
  
                                                                5
“ Tenant Improvements ”), and (ii) November 1, 2013 and (z) the date on which Tenant has occupied any portion of the Phase 2 
Premises for the conduct of its business, as opposed to occupying any portion of the Phase 2 Premises for the installation of
the Tenant Improvements. Each of the Phase 1 Premises Rent Commencement Date and the Phase 2 Premises Rent
Commencement Date shall be subject to extension for Landlord Delay as further described in Section 4 of Exhibit B hereto. Each
party shall execute and deliver to the other written acknowledgment of the actual Commencement Date, the actual Phase 1
Premises Rent Commencement Date, the actual Phase 2 Premises Rent Commencement Date and/or the Term Expiration Date
within ten (10) business days after request by the other party, substantially in the form attached as Exhibit C hereto. Failure to
execute and deliver such acknowledgment, however, shall not affect the Phase 1 Premises Rent Commencement Date, the Phase
2 Premises Rent Commencement Date, the Term Expiration Date or Landlord’s or Tenant’s liability hereunder. The term “ 
Substantially Complete ” or “ Substantial Completion ” means that the applicable Phase of Tenant Improvements is
substantially complete in accordance with the Approved Plans (as defined in Exhibit B hereto), except for minor punch list items,
and that Tenant is able to lawfully occupy the Premises for the conduct of its business in accordance with the Permitted Use.

      4.2. Tenant shall cause the Tenant Improvements to be constructed in the Premises pursuant to the Work Letter attached
hereto as Exhibit B (the “ Work Letter ”) at a cost to Landlord not to exceed Eighteen Million Nine Hundred Nine Thousand
Seven Hundred Fifty and 00/100 Dollars ($18,909,750.00) (based upon One Hundred Fifty and 00/100 Dollars ($150.00) per
square foot of Rentable Area (as defined below)) (the “ TI Allowance ”). The TI Allowance may be applied to the costs of
(s) construction, (t) building permits and other permits, approvals, taxes, fees, charges and levies by Governmental Authorities 
(as defined below) for permits or for inspections of the Tenant Improvements, and (u) costs and expenses for labor, material, 
equipment and fixtures. In no event shall the TI Allowance be used for (v) the cost of work that is not authorized by the 
Approved Plans (as defined in the Work Letter) or otherwise approved in writing by Landlord, (w) payments to Tenant or any 
affiliates of Tenant, (x) Tenant’s soft costs or the purchase of any furniture, personal property or other non-building system
equipment, (y) costs resulting from any default by Tenant of its obligations under this Lease or (z) costs to extent recoverable 
by Tenant from a third party (e.g., insurers, warrantors, or tortfeasors). Notwithstanding the foregoing to the contrary, Tenant
may apply up to ten percent (10%) of the TI Allowance toward the costs of Tenant’s architectural, engineering, and project
management fees, data/telecom cabling, relocation expenses, and an additional amount up to ten percent (10%) of the TI 
Allowance towards the costs of Tenant’s furniture, fixtures and equipment installation related to the initial occupancy of the
Premises. In no event shall any unused TI Allowance entitle Tenant to a credit against Rent payable under this Lease. Tenant
shall have until May 31, 2014 (the “ TI Deadline ”) to requisition the unused portion of the TI Allowance, after which date
Landlord’s obligation to fund such costs shall expire.

     4.3. The Phase 1 Premises and Phase 2 Premises are sometimes generically referred to herein as a “Phase”.
  
                                                                6
    4.4. Prior to entering upon the Premises, Tenant shall furnish to Landlord evidence satisfactory to Landlord that insurance
coverages required of Tenant under the provisions of Article 23 are in effect.

5. Condition of Premises . Tenant acknowledges that neither Landlord nor any agent of Landlord has made any
representation or warranty with respect to the condition of the Premises, the Building or the Property, or with respect to
the suitability of the Premises, the Building or the Property for the conduct of Tenant’s business, except as expressly set
forth in this Lease. Without in any way derogating from Landlord’s ongoing maintenance, repair and restoration
obligations set forth elsewhere in this Lease, Tenant acknowledges that (a) it is familiar with the condition of the Premises 
and agrees to take the same in its condition “as is” as of the Execution Date and (b) Landlord shall have no obligation to 
alter, repair or otherwise prepare the Premises for Tenant’s occupancy or to pay for or construct any improvements to the
Premises, except with respect to the TI Allowance; provided, however, that Landlord shall separately demise that portion
of the Premises located on the fourth (4th) floor of the Building separately as shown on Exhibit B-1 attached hereto and
furnish and provide a reception desk in the main building lobby as further provided in Exhibit B , at Landlord’s sole cost
and expense (in addition to the TI Allowance).

6. Rentable Area . The Rentable Areas initially set forth herein are deemed conclusive between the parties and are not subject to
remeasurement, except that in the event that the size of the Premises or Building is actually reduced or expanded pursuant to the
provisions of Articles 1, 24, 25, 43 or 44 below, the Rentable Areas (and, as applicable, Tenant’s Pro Rata Share) shall be
adjusted as reasonably calculated by Landlord’s architect in a manner consistent with Landlord’s initial determination of
Rentable Areas for the Premises and the Building.

7. Rent .
     7.1. Tenant shall pay to Landlord as Base Rent for the Premises, commencing on the Phase 1 Premises Rent
Commencement Date, the sums set forth in Section 2.3 , subject to the rental adjustments provided in Section 4.1 and Article 8
hereof. Base Rent shall be paid in equal monthly installments, subject to the rental adjustments provided in Section 4.1 and
Article 8 hereof, each in advance on the first day of each and every calendar month during the Term.

      7.2. In addition to Base Rent, Tenant shall pay to Landlord as additional rent (“ Additional Rent ”) at times hereinafter
specified in this Lease (a) Tenant’s Share (as defined below) of Operating Expenses (as defined below), (b) the Property 
Management Fee (as defined below) and (c) any other amounts that Tenant assumes or agrees to pay under the provisions of 
this Lease that are owed to Landlord, including any and all other sums that may become due by reason of any default of Tenant
or failure on Tenant’s part to comply with the agreements, terms, covenants and conditions of this Lease to be performed by
Tenant, after notice and the lapse of any applicable cure periods.

     7.3. Base Rent and Additional Rent shall together be denominated “Rent.” Rent shall be paid to Landlord in lawful money
of the United States of America at the office of Landlord as set forth in Section 2.8 or to such other person or at such other 
place as Landlord may from time designate in writing. In the event the Phase 1 Rent Commencement Date or Phase 2 Rent
  
                                                                 7
Commencement Date occurs or the Term ends on a day other than the first day of a calendar month, then the Rent for such
fraction of a month shall be prorated for such period on the basis of a thirty (30) day month and shall be paid at the then-current
rate for such fractional month. All payments of Rent shall be made without set-off, deduction or offset except as expressly
provided in this Lease. Without limiting the foregoing, Tenant’s obligation to pay Rent shall be absolute, unconditional, and
independent and shall not be discharged or otherwise affected by any Applicable Laws now or hereafter applicable to the
Premises, or any other restriction on Tenant’s use, or, except as provided in Articles 24 and 25 , any casualty or taking, or any
failure by Landlord to perform or other occurrence; and Tenant assumes the risk of the foregoing and waives all rights now or
hereafter existing to quit or surrender the Premises or any part thereof, to terminate or cancel this Lease, or to assert any defense
in the nature of constructive eviction in any action seeking to recover rent (other than mandatory counterclaims). Subject to the
provisions of this Lease, however, Tenant shall have the right to injunctive relieve or to seek judgments for direct money
damages occasioned by Landlord’s breach of its Lease covenants (but may not set-off any such judgment against any rent or
other amount owing hereunder). Nothing in this Section 7.3 shall limit the exercise of Tenant’s express remedies on the terms
and conditions set forth in Sections 16.2 and  18.3 below).

8. Rent Adjustments . Base Rent shall be subject to an annual upward adjustment of three percent (3%) of the then-current Base
Rent during the initial Term. The first such adjustment shall become effective commencing on the first (1 st ) annual anniversary 
of the Phase 1 Premises Rent Commencement Date, and subsequent adjustments shall become effective on every successive
annual anniversary for the remainder of the initial Term of this Lease.

9. Operating Expenses .
     9.1. As used herein, the term “ Operating Expenses ” shall include:

           (a) Government impositions, including property tax costs consisting of real and personal property taxes and
assessments (including amounts due under any improvement bond upon the Building or the Property (including the parcel or
parcels of real property upon which the Building, the other buildings on the Property and areas serving the Building and the
Property are located)) or assessments in lieu thereof imposed by any federal, state, regional, local or municipal governmental
authority, agency or subdivision (each, a “ Governmental Authority ”); taxes on or measured by gross rentals received from the
rental of space in the Property; taxes based on the square footage of the Premises, the Building or the Property, as well as any
parking charges, utilities surcharges or any other costs levied, assessed or imposed by, or at the direction of, or resulting from
Applicable Laws or interpretations thereof, promulgated by any Governmental Authority in connection with the use or
occupancy of the Building or Property or the parking facilities serving the Building; any actual and reasonable third party
expenses, including the reasonable cost of attorneys or experts, reasonably incurred by Landlord in seeking reduction by the
taxing authority of the applicable taxes. If Landlord is successful in obtaining any refund, abatement or other reduction of any
taxes payable in respect of the Property for any year for which Tenant has paid Operating Expenses, Landlord shall promptly
refund to Tenant Tenant’s Pro Rata Share of the Building of such refund, abatement or other reduction (including any interest
paid by the taxing authority),
  
                                                                 8
but in any event not to exceed amounts actually paid by Tenant on account of such taxes during such period. To the extent that
Landlord is billed for any taxes on the execution of this Lease or any other document to which Tenant is a party creating or
transferring an interest in the Premises, Tenant shall pay the same directly to Landlord within thirty (30) days after receipt of an 
invoice therefor (which invoice shall be accompanied by a copy of the applicable tax bill(s)). Operating Expenses shall not
include any state, federal or local net income, franchise, capital stock, estate, transfer or inheritance taxes, or taxes that are the
personal obligation of Tenant or of another tenant of the Property; and

           (b) All other actual third party costs (or costs for Landlord personnel or services provided by Landlord so long as the
same is provided at a cost that does not exceed the cost of such personnel or service rendered by unaffiliated third parties on a
competitive basis) of any kind paid or incurred by Landlord in connection with the operation or maintenance of the Building and
the Property, including costs of repairs and replacements to improvements within the Property as appropriate to maintain the
Property as required hereunder; costs of utilities furnished to the Common Areas; sewer fees; trash collection (including
recyclables, but excluding special handling or collection costs associated with collection of any Hazardous Materials not
customarily collected in the ordinary maintenance of a first class office and laboratory building); Common Area cleaning,
including windows; heating; ventilation; air-conditioning; maintenance of landscaping and grounds; maintenance of drives and
parking areas; maintenance of the roof; security services and devices; building supplies; maintenance or replacement of
equipment utilized for operation and maintenance of the Property; license, permit and inspection fees; sales, use and excise
taxes on goods and services purchased by Landlord in connection with the operation, maintenance or repair of the Building or
Property systems and equipment; telephone, postage, stationery supplies and other expenses incurred in connection with the
operation, maintenance or repair of the Property; accounting, legal and other professional fees and expenses incurred in
connection with the Property; costs of furniture, draperies, carpeting, landscaping, snow removal and other customary and
ordinary items of personal property provided by Landlord for use in Common Areas; Property office rent or rental value for a
commercially reasonable amount of space, to the extent an office used for Property operations is maintained at the Property,
plus customary expenses for such office; capital expenditures amortized over the useful life thereof, as reasonably determined
by Landlord, in accordance with generally accepted accounting principles ; costs of complying with Applicable Laws (except to
the extent such costs are incurred to remedy non-compliance as of the Execution Date with Applicable Laws); costs to keep the
Property in compliance with, or fees otherwise required under, any Property Operations Agreements (as defined below);
insurance premiums; portions of insured losses paid by Landlord as part of a deductible portion of a loss pursuant to the terms
of insurance policies (provided that such deductibles are commercially reasonable); service contracts; costs of services of
independent contractors retained to do work of a nature referenced above; and costs of compensation (including employment
taxes and fringe benefits) of all persons who perform regular and recurring duties connected with the day-to-day operation and
maintenance of the Property, its equipment, the adjacent walks, landscaped areas, drives and parking areas, including janitors,
floor waxers, window washers, watchmen, gardeners, sweepers, plow trucks and handymen. Operating Expenses for each year
will be calculated in a reasonably consistent manner.
  
                                                                  9
            (c) Notwithstanding the foregoing, Operating Expenses shall not include any (i) leasing commissions; (ii) expenses 
that relate to preparation of rental space for a tenant; (iii) expenses of initial development and construction of the Building, or of 
any expansion or elective upgrade (other than for the primary purpose of reducing Operating Expenses as described in clause
(x) below) of the Building or Common Areas, including grading, paving, landscaping and decorating (as distinguished from 
maintenance, repair and replacement of the foregoing); (iv) legal expenses relating to other tenants; (v) costs of repairs to the 
extent Landlord is entitled to be reimbursed by payment of insurance, warranties or guaranties or by any other third party or
parties; (vi) principal amount of, or interest upon loans to Landlord or secured by a mortgage or deed of trust covering the 
Property or a portion thereof; (vii) costs to operate, maintain, or repair the Garage; (viii) salaries of executive officers of 
Landlord; (ix) depreciation claimed by Landlord for tax purposes (other than amortization of capital expenditures as expressly 
provided herein); (x) capital improvements (as distinguished from repairs and maintenance) unless and except to the extent 
incurred (i) in replacing obsolete equipment or other capital items, (ii) for the primary purpose of reducing Operating Expenses or 
(iii) required by any Governmental Authority to comply with changes in Applicable Laws that take effect after the Execution 
Date or to ensure continued compliance with Applicable Laws in effect as of the Execution Date (but expressly excluding the
costs of curing or contesting violations of Applicable Law that existed on or prior to the Execution Date); (xi) the cost of 
leasehold improvements, including without limitation redecorating or renovation work, for other tenants in the Building; (xii) to 
the extent of any increase in Landlord’s insurance rates which may result from the grossly negligent failure of Landlord or its
agents, employees or contractors to comply with the provisions of this Lease; (xiii) the cost of any work or service performed 
for any tenant in the Building (other than Tenant) to a materially greater extent or in a materially more favorable manner than that
furnished generally to tenants (including Tenant) in the Building; (xiv) the general corporate overhead costs and expenses of 
the Landlord entity (except to the extent of the Property Management Fee and personnel costs at the level of Senior Property or
Facilities Manager and below to the extent related to the Property); (xv) costs and expenses incurred in any dispute with any 
particular tenant; (xvi) any costs of remediation of hazardous materials or substances in the Building, or on the land parcels on 
which it is located; (xvii) any costs (other than the Property Management Fee described below) representing an amount paid to 
an entity related to Landlord which is in excess of the amount which would have been paid absent such relationship; and
(xviii) taxes that are excluded from Operating Expenses by the last sentence of Subsection 9.1(a) . To the extent that Tenant uses
more than Tenant’s Pro Rata Share of the Building of any item of Operating Expenses, Landlord shall provide notice to Tenant
of such excess usage, and Tenant shall pay Landlord for such excess in addition to Tenant’s obligation to pay Tenant’s Pro
Rata Share of Lab Building of Operating Expenses for the Property (such excess, together with Tenant’s Pro Rata Share of Lab
Building, “ Tenant’s Share ”). Notwithstanding anything in this Article 9 to the contrary, Tenant’s Share with respect to taxes
and other impositions as set forth in Subsection 9.1(a) and to expenses payable by the Building under the CC&Rs shall mean
such excess together with Tenant’s Pro Rata Share of the Building. Nothing in this paragraph shall be deemed to limit the extent
to which CC&Rs are included in Operating Expenses.

    9.2. Tenant shall pay to Landlord on the first day of each calendar month of the Term, following the Phase 1 Premises Rent
Commencement Date, as Additional Rent, (a) the Property Management Fee (as defined below) and (b) Landlord’s estimate of
Tenant’s Share of Operating Expenses for such month.
  
                                                                  10
          (x) The “ Property Management Fee ” shall equal three percent (3%) of Base Rent due from Tenant. Tenant shall pay 
the Property Management Fee in accordance with Section 9.2 with respect to the entire Term, commencing on the applicable
Rent Commencement Date, including any extensions thereof or any holdover periods, regardless of whether Tenant is obligated
to pay Base Rent, Operating Expenses or any other Rent with respect to any such period or portion thereof, except as expressly
provided in this Lease.

           (y) Within ninety (90) days after the conclusion of each calendar year (or such longer period as may be reasonably 
required by Landlord but in any event not to exceed one year), Landlord shall furnish to Tenant a statement showing in
reasonable detail the actual Operating Expenses and Tenant’s Share of Operating Expenses for the previous calendar year. Any
additional sum due from Tenant to Landlord shall be due and payable within thirty (30) days. If the amounts paid by Tenant 
pursuant to this Section exceed Tenant’s Share of Operating Expenses for the previous calendar year, then Landlord shall credit
the difference against Tenant’s Share of Operating Expenses next due and owing from Tenant; provided that, if the Term has
expired, Landlord shall accompany such statement with payment for the amount of such difference.

          (z) Any amount due under this Section for any period that is less than a full month shall be prorated (based on a thirty
(30)-day month) for such fractional month.

      9.3. Landlord’s annual statement shall be final and binding upon Tenant unless Tenant, within 180 days after Tenant’s
receipt thereof, shall contest any item therein by giving written notice to Landlord, specifying in reasonable detail the reasons
therefor; provided that Tenant shall in all events pay the amount specified in Landlord’s annual statement, pending the results
of the Independent Review and determination of the Accountant(s), as applicable and as each such term is defined below. At
the request of Tenant at any time within such 180-day period, Landlord shall provide Tenant with reasonable access to
Landlord’s books and records to the extent relevant to determination of Operating Expenses, and such information as Landlord
reasonably determines to be responsive to Tenant’s written inquiries. In the event that, after Tenant’s review of such
information, Landlord and Tenant cannot agree upon the amount of Tenant’s Share of Operating Expenses, then Tenant shall
have the right to have a qualified and reputable third party consultant or accounting firm hired by Tenant (but not on a
contingent-fee basis) at Tenant’s sole cost and expense audit and review such of Landlord’s books and records for the year in
question as directly relate to the determination of Operating Expenses for such year (the “ Independent Review ”). Landlord
shall make such books and records available at the location where Landlord maintains them in the ordinary course of its
business, but need not provide Tenant with copies of any books or records. Tenant shall commence the Independent Review
within thirty (30) days after the date Landlord has given Tenant access to Landlord’s books and records for the Independent
Review and following at least 10 days’ prior notice to Landlord of the identity of the consultant or accounting firm conducting
such review so that Landlord can confirm that such reviewer meets the foregoing qualifications. Tenant shall complete the
Independent Review and notify Landlord in writing of
  
                                                                11
Tenant’s specific objections to Landlord’s calculation of Operating Expenses (including Tenant’s accounting firm’s written
statement of the basis, nature and amount of each proposed adjustment) no later than sixty (60) days after Landlord has first 
given Tenant access to Landlord’s books and records for the Independent Review. Landlord shall review the results of any
such Independent Review. The parties shall endeavor to agree promptly and reasonably upon Operating Expenses taking into
account the results of such Independent Review. If, as of sixty (60) days after Tenant has submitted the Independent Review to 
Landlord, the parties have not agreed on the appropriate adjustments to Operating Expenses, then the parties shall engage a
mutually agreeable independent third party accountant with at least ten (10) years’ experience in commercial real estate
accounting in the Kendall Square, Cambridge, Massachusetts area (the “ Accountant ”). If the parties cannot agree on the
Accountant, each shall within ten (10) days after such impasse appoint an Accountant (different from the accountant and 
accounting firm that conducted the Independent Review) and, within ten (10) days after the appointment of both such 
Accountants, those two Accountants shall select a third (which cannot be the accountant and accounting firm that conducted
the Independent Review). If either party fails to timely appoint an Accountant, then the Accountant the other party appoints
shall be the sole Accountant. Within ten (10) days after appointment of the Accountant(s), Landlord and Tenant shall each 
simultaneously give the Accountants (with a copy to the other party) its determination of Operating Expenses, with such
supporting data or information as each submitting party determines appropriate. Within ten (10) days after such submissions, 
the Accountants shall by majority vote select either Landlord’s or Tenant’s determination of Operating Expenses. The
Accountants may not select or designate any other determination of Operating Expenses. The determination of the Accountant
(s) shall bind the parties. If the parties agree or the Accountant(s) determine that the Operating Expenses actually paid by
Tenant for the calendar year in question exceeded Tenant’s obligations for such calendar year, then Landlord shall, at Tenant’s
option, either (a) credit the excess to the next succeeding installments of estimated Additional Rent or (b) pay the excess to 
Tenant within thirty (30) days after delivery of such results. If the parties agree or the Accountant(s) determine that Tenant’s
payments of Operating Expenses for such calendar year were less than Tenant’s obligation for the calendar year, then Tenant
shall pay the deficiency to Landlord within thirty (30) days after delivery of such results. If the Independent Review reveals or 
the Accountant(s) determine that the Operating Expenses billed to Tenant by Landlord and paid by Tenant to Landlord for the
applicable calendar year in question exceeded by more than four percent (4%) what Tenant should have been billed during such 
calendar year, then Landlord shall pay the reasonable cost of the Independent Review and the Accountants. In all other cases,
Tenant shall pay the cost of the Independent Review, and one-half of the cost of the Accountants. Any Operating Expense not
billed to Tenant on or before the second (2 nd ) anniversary of the last day of the calendar year in which such Operating Expense 
was billed to or incurred by Landlord shall be deemed waived by Landlord, and Tenant shall have no liability or obligation with
respect thereto.

     9.4. Tenant shall not be responsible for Operating Expenses attributable to the time period prior to the Phase 1 Premises
Rent Commencement Date, with respect to the Phase 1 Premises; or the Phase 2 Premises Rent Commencement Date, with
respect to the Phase 2 Premises.
     9.5. Operating Expenses for the calendar year in which Tenant’s obligation to share therein commences and for the
calendar year in which such obligation ceases shall be prorated
  
                                                               12
on a commercially reasonable basis determined by Landlord and consistent with generally accepted commercial property
accounting principles. Expenses such as taxes, assessments and insurance premiums that are incurred for an extended time
period shall be prorated based upon the time periods to which they apply so that the amounts attributed to the Premises relate
in a reasonable manner to the time period wherein Tenant has an obligation to share in Operating Expenses.

     9.6. In the event that the Building is less than fully occupied, Tenant acknowledges that Landlord may extrapolate those
particular items of Operating Expenses that vary depending on the occupancy of the Building to reflect the amount that would
have been incurred for those particular expenses had the entire Building been occupied during such period; provided , however,
that Landlord shall not recover more than one hundred percent (100%) of Operating Expenses. 

10. Taxes on Tenant’s Property .
      10.1. Tenant shall be responsible for any and all taxes levied against any personal property or trade fixtures placed by
Tenant in or about the Premises. Tenant shall not be deemed to be in default of its obligations under the preceding sentence in
the event that Tenant shall contest the validity of any such taxes by appellate or other proceedings permitted under Applicable
Laws, provided that: (a) any such contest is made reasonably and in good faith, (b) Tenant makes commercially reasonable 
provisions reasonably acceptable to Landlord (which shall include posting bond(s) or giving other security satisfactory to
Landlord if the Building or the Property are subjected to any liens arising out of such failure to pay or contest, with Tenant in
each case agreeing to discharge or bond over any such liens within 15 days after such liens arise) to protect Landlord, the
Building and the Property from any liabilities, costs, damages and expenses arising in connection with Tenant’s inability to pay,
or the contest of, such taxes, (c) Tenant agrees to indemnify, defend (with counsel reasonably acceptable to Landlord) and hold 
Landlord harmless from and against any and all liabilities, costs, damages and expenses arising in connection with Tenant’s
failure to pay, or contest of, such taxes as required by Applicable Law, and (d) Tenant promptly pays any and all such taxes in 
the event that it exhausts all available appeals without success or if such payment is required as a precondition to such contest.

      10.2. If (a) (i) any such taxes on Tenant’s personal property or trade fixtures are levied against Landlord or Landlord’s
property, or (ii) the assessed valuation of the Building or the Property is increased by inclusion therein of a value specifically 
attributed to Tenant’s personal property or trade fixtures, as evidenced by information provided in writing by the tax assessor,
and (b) Landlord, after written notice to Tenant, pays the taxes on Tenant’s personal property or trade fixtures, then Tenant
shall, upon demand, repay to Landlord the taxes so paid by Landlord.
  
                                                                 13
11. Security Deposit .
     11.1. Tenant shall deposit with Landlord on or before the Execution Date a letter of credit (the “ L/C Security ”) as the entire
security deposit (the “ Security Deposit ”), as follows:

            (a) Tenant shall provide Landlord, and maintain in full force and effect throughout the Term and until the date that is
ninety (90) days after the then-current Term Expiration Date, a letter of credit substantially in the form of Exhibit E issued by an
issuer reasonably satisfactory to Landlord, in the amount of the Security Deposit, with an initial term of at least one year.
Landlord may require the L/C Security to be replaced by an L/C Security issued by a different issuer at any time during the Term
if Landlord reasonably believes that the issuing bank of the L/C Security is or may soon become insolvent, in which event
Landlord shall cooperate with Tenant to arrange for the replacement of the L/C Security in a manner that does not require the
simultaneous issuance of two (2) letters of credit. If Tenant has actual notice, or Landlord notifies Tenant at any time, that any 
issuer of the L/C Security has become insolvent or placed into FDIC receivership, then Tenant shall promptly deliver to
Landlord (without the requirement of further notice from Landlord) substitute L/C Security issued by an issuer reasonably
satisfactory to Landlord, and otherwise conforming to the requirements set forth in this Article. As used herein with respect to
the issuer of the L/C Security, “insolvent” shall mean the determination of insolvency as made by such issuer’s primary bank
regulator (i.e., the state bank supervisor for state chartered banks; the OCC or OTS, respectively, for federally chartered banks
or thrifts; or the Federal Reserve for its member banks).

            (b) Landlord may draw upon the L/C Security, and hold and apply the proceeds for the payment of any Rent or any
other sum in default, or to compensate Landlord for any other loss or damage that Landlord may suffer by reason of Tenant’s
default, if: (i) a Default (as defined below) exists (or would have existed with the giving of notice and passage of applicable cure 
periods, but only if transmittal of a default notice is stayed or barred by applicable bankruptcy or other similar law), provided
that such draw pursuant to his clause (i) shall be limited to the amount that Landlord reasonably determines is required to cure 
such Default; (ii) as of the date forty-five (45) days before any L/C Security expires Tenant has not delivered to Landlord an 
amendment or replacement for such L/C Security, reasonably satisfactory to Landlord, extending the expiry date to the earlier of
(1) ninety (90) days after the then-current Term Expiration Date or (2) the date one year after the then-current expiry date of the
L/C Security; (iii) Tenant fails to pay (when and as Landlord reasonably requires) any bank charges for Landlord’s transfer of
the L/C Security; or (iv) the issuer of the L/C Security ceases, or announces that it will cease, to maintain an office in the city 
where Landlord may present drafts under the L/C Security (and fails to permit drawing upon the L/C Security by overnight
courier or facsimile). This Section does not limit any other provisions of this Lease allowing Landlord to draw the L/C Security
under specified circumstances. In the event of any such draw upon the L/C Security, Tenant shall within 10 days thereafter
provide Landlord with a replacement letter of credit, or amendment to the existing letter of credit increasing the amount of such
letter of credit, in the amount of L/C Security required hereunder, and Tenant’s failure to do so shall be a material breach of this
Lease. Landlord shall hold the proceeds of any draw not applied as set forth above as a cash Security Deposit as further
described below.

            (c) If Landlord transfers its interest in the Premises, then Landlord shall transfer the L/C Security to the transferee of
its interest, and Tenant shall at Tenant’s expense, within fifteen (15) business days after receiving a request from Landlord, 
deliver (and, if the issuer requires, Landlord shall consent to) an amendment to the L/C Security naming Landlord’s grantee as
substitute beneficiary. If the required Security Deposit changes while L/C Security is in force, then Tenant shall deliver (and, if
the issuer requires, Landlord shall consent to) a corresponding amendment to the L/C Security.
  
                                                                  14
           (d) If and to the extent Landlord is holding the proceeds of the L/C Security in cash from time to time, such cash shall
be held by Landlord as security for the faithful performance by Tenant of all of the terms, covenants and conditions of this
Lease to be kept and performed by Tenant during the period commencing on the Execution Date and ending upon the expiration
or termination of Tenant’s obligations under this Lease. If Tenant Defaults with respect to any provision of this Lease,
including any provision relating to the payment of Rent, then Landlord may (but shall not be required to) use, apply or retain all
or any part of the Security Deposit for the payment of any Rent or any other sum in Default, or to compensate Landlord for any
other loss or damage that Landlord may suffer by reason of Tenant’s Default as provided in this Lease. The provisions of this
Article shall survive the expiration or earlier termination of this Lease. In the event of bankruptcy or other debtor-creditor
proceedings against Tenant, any cash Security Deposit then being held by Landlord shall be deemed to be applied first to the
payment of Rent and other charges due Landlord for all periods prior to the filing of such proceedings. Landlord shall deliver or
credit to any purchaser of Landlord’s interest in the Premises the funds then held hereunder by Landlord, and thereupon (and
upon confirmation by the transferee of such funds, whether expressly or by written assumption of this Lease, generally)
Landlord shall be discharged from any further liability with respect to such funds. This provision shall also apply to any
subsequent transfers. If Tenant shall fully and faithfully perform every provision of this Lease to be performed by it, then the
Security Deposit, if any, or any balance thereof, shall be returned to Tenant (or, at Landlord’s option, to the last assignee of
Tenant’s interest hereunder) within 90 days after the expiration or earlier termination of this Lease. If and to the extent the
Security Deposit shall be in cash, Landlord shall hold the Security Deposit in an account at a banking organization selected by
Landlord; provided , however, that Landlord shall not be required to maintain a separate account for the Security Deposit, but
may intermingle it with other funds of Landlord. Landlord shall be entitled to all interest and/or dividends, if any, accruing on
the Security Deposit. Landlord shall not be required to credit Tenant with any interest for any period during which Landlord
does not receive interest on the Security Deposit.

12. Use .
     12.1. Tenant shall use the Premises for the purpose set forth in Section 2.7 , and shall not use the Premises, or permit or
suffer the Premises to be used, for any other purpose without Landlord’s prior written consent, which consent Landlord may
withhold in its sole and absolute discretion.

     12.2. Tenant shall not use or occupy the Premises in violation of Applicable Laws; zoning ordinances; or the certificate of
occupancy issued for the Building or the Property, and shall, upon five (5) days’ written notice from Landlord, discontinue any
use of the Premises that is declared or claimed by any Governmental Authority having jurisdiction to be a violation of any of the
above, or that in Landlord’s reasonable opinion violates any of the above. Tenant shall comply with any direction of any
Governmental Authority having jurisdiction that shall, solely by reason of the nature of Tenant’s use or occupancy of the
Premises (other than for general office or laboratory use), impose any duty upon Tenant or Landlord with respect to the
Premises or with respect to the use or occupation thereof.
  
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      12.3. Tenant shall not do or permit to be done anything that will invalidate or increase the cost of any fire, environmental,
extended coverage or any other insurance policy covering the Building or the Property, and shall comply with all commercially
reasonable and customary rules, orders, regulations and requirements of the insurers of the Building and the Property, and
Tenant shall promptly, upon demand, reimburse Landlord for any additional premium charged for such policy solely by reason
of Tenant’s failure to comply with the provisions of this Article, or cease the applicable activity, to the extent that ceasing such
activity does in fact prevent such cost increase from occurring. The use of the Premises for office or laboratory uses, generally,
will not result in a breach of the provisions of this paragraph.

     12.4. Tenant shall keep all doors opening onto public corridors closed, except when in use for ingress and egress.

     12.5. No additional locks or bolts of any kind shall be placed upon any of the doors or windows by Tenant, nor shall any
changes be made to existing locks or the mechanisms thereof without Landlord’s prior written consent. Tenant shall, upon
termination of this Lease, return to Landlord all keys to offices and restrooms either furnished to or otherwise procured by
Tenant. In the event any key so furnished to Tenant is lost, Tenant shall pay to Landlord the cost of replacing the same or of
changing the lock or locks opened by such lost key if Landlord shall deem it necessary to make such change.

     12.6. No awnings or other projections shall be attached to any outside wall of the Building. No curtains, blinds, shades or
screens shall be attached to or hung in, or used in connection with, any exterior or atrium window or door of the Premises other
than Landlord’s standard window coverings as described in the Tenant Manual. Neither the interior nor exterior of any
windows shall be coated or otherwise sunscreened without Landlord’s prior written consent, nor shall any bottles, parcels or
other articles be placed on the windowsills. No equipment, furniture or other items of personal property shall be placed on any
exterior balcony without Landlord’s prior written consent.

     12.7. No sign, advertisement or notice (“ Signage ”) shall be exhibited, painted or affixed by Tenant on any part of the
Premises or the Building without Landlord’s prior written consent, which may be withheld in Landlord’s sole discretion, except
as expressly set forth in this Section 12.7. Tenant shall be entitled to install and maintain, at its sole cost and expense, (1) one 
exterior sign identifying Tenant on the facade of the Building to be located within the area designated on Exhibit L attached
hereto, and (2) interior entry signage on doors to the Premises in Landlord’s reasonable discretion (to the extent visible from
Common Areas) and in a manner consistent with Landlord’s reasonable Building Standards, subject in each case to all
Applicable Laws, codes and ordinances and Landlord’s reasonable approval with regards to installation, size, design, location
and other reasonable criteria (provided, however, the standard corporate lettering and logo of Tenant are hereby approved). For
any Signage, Tenant shall, at Tenant’s own cost and expense, (a) acquire all permits for such Signage in compliance with 
Applicable Laws and (b) design, fabricate, install and maintain such Signage in a first-class condition. Tenant shall be
responsible for removing any of Tenant’s Signage upon the expiration
  
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or earlier termination of this Lease. The directory tablet shall be inscribed, painted or affixed for Tenant by Landlord at
Landlord’s sole cost and expense, and shall be of a size, color and type and be located in a place acceptable to Landlord. The
directory tablet shall be provided exclusively for the display of the name and location of tenants only. Tenant shall not place
anything on the exterior of the corridor walls or corridor doors other than Landlord’s standard lettering.

     12.8. Tenant shall only place equipment within the Premises with floor loading consistent with the Building’s structural
design (which is 100 psf) without Landlord’s prior written approval, and such equipment shall be placed in a location designed
to carry the weight of such equipment.

     12.9. Tenant shall cause any equipment or machinery to be installed in the Premises so as to reasonably prevent sounds or
vibrations therefrom from extending into the Common Areas or other offices in the Property.

     12.10. Tenant shall not (a) do or permit anything to be done in or about the Premises that shall in any way unreasonably 
obstruct or interfere with the rights of other tenants or occupants of the Property, or injure them, (b) use or allow the Premises 
to be used for unlawful purposes, (c) cause, maintain or permit any nuisance or waste in, on or about the Property or (d) take 
any other action that would in Landlord’s reasonable determination in any manner unreasonably and adversely affect other
tenants’ quiet use and enjoyment of their space or adversely impact their ability to conduct business in a professional and
suitable work environment for office and laboratory uses.

      12.11. Landlord shall be responsible for ensuring the Common Areas comply with the Americans with Disabilities Act, 42
U.S.C. § 12101, et seq., and any state and local accessibility laws, codes, ordinances and rules (collectively, and together with 
regulations promulgated pursuant thereto, the “ ADA ”) to (which cost may be included in Operating Expenses) and that the
Landlord Demising Work is performed in compliance with the ADA. Subject to the foregoing, Tenant shall be responsible for all
liabilities, costs and expenses arising out of or in connection with the compliance of the Premises with the ADA, and Tenant
shall indemnify, save, defend (at Landlord’s option and with counsel reasonably acceptable to Landlord) and hold Landlord and
its affiliates, employees, agents and contractors; and any lender, mortgagee or beneficiary (each, a “ Lender ” and, collectively
with Landlord and its affiliates, employees, agents and contractors, the “ Landlord Indemnitees ”) harmless from and against
any demands, claims, liabilities, losses, costs, expenses, actions, causes of action, damages or judgments, and all reasonable
expenses (including reasonable attorneys’ fees, charges and disbursements) incurred in investigating or resisting the same
(collectively, “ Claims ”) arising out of any such failure of the Premises to comply with the ADA. This Section (as well as any
other provisions of this Lease dealing with indemnification of the Landlord Indemnitees by Tenant shall be deemed to be
modified in each case by the insertion in the appropriate place of the following: “except as otherwise provided in Mass. G.L. Ter.
Ed., C. 186, Section 15.” The provisions of this Section shall survive the expiration or earlier termination of this Lease.
  
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      12.12. Tenant shall establish and maintain a chemical safety program administered by a licensed, qualified individual in
accordance with the requirements of the Massachusetts Water Resources Authority (“ MWRA ”) and any other applicable
Governmental Authority. Tenant shall be solely responsible for all costs incurred in connection with such chemical safety
program, and Tenant shall provide Landlord with such documentation as Landlord may reasonably require evidencing Tenant’s
compliance with the requirements of (a) the MWRA and any other applicable Governmental Authority with respect to such 
chemical safety program and (b) this Section. Tenant shall not introduce anything into the sewer system serving the Building 
(x) in violation Applicable Laws. Landlord agrees to reasonably cooperate with Tenant, at no unreimbursed cost to Landlord, in 
order for Tenant to obtain any MWRA permit and wastewater treatment operator license required for Tenant’s operations.
Tenant shall reimburse Landlord within ten (10) business days after demand for any third party costs reasonably incurred by 
Landlord in cooperating with Tenant pursuant to this Section.

13. Rules and Regulations, CC&Rs, Parking Facilities and Common Areas .
      13.1. Tenant shall have the non-exclusive right, in common with others, to use the Common Areas in conjunction with
Tenant’s use of the Premises for the Permitted Use (including without limitation such Common Areas as are reasonably
designated by Landlord for the connection of any equipment located in off-floor mechanical areas that are contained within the
Premises to the applicable occupied floor of the Premises), and such use of the Common Areas and Tenant’s use of the
Premises shall be subject to the rules and regulations and tenant manual governing Alterations, each as adopted by Landlord
and initially attached hereto as Exhibit F , together with such other reasonable and nondiscriminatory rules and regulations as
are hereafter promulgated by Landlord of which Tenant is given prior written notice (collectively, the “ Rules and Regulations
”), provided, however, that in the case of any conflict between the provisions of this Lease and any such Rules and
Regulations, the provisions of this Lease shall control. Tenant shall faithfully observe and comply with the Rules and
Regulations. Landlord shall use reasonable efforts to enforce the Rules and Regulations against Tenant or any other tenant of
the Building or Property, but shall have no responsibility for any violations thereof. Landlord shall not enforce the Rules and
Regulations in a discriminatory manner against Tenant.

     13.2. This Lease is subject to any recorded covenants, conditions or restrictions on the Property (the “ CC&R ”), to the
Development Approvals (as defined on Exhibit D ), and to any other matters of record, in each case as the same may be
amended, amended and restated, supplemented or otherwise modified from time to time (collectively, the “ Property Operations
Agreements ”; provided that any such amendments, restatements, supplements or modifications do not materially modify
Tenant’s rights or obligations or Landlord’s obligations hereunder. Each of Landlord and Tenant, in the exercise of their
respective rights and the performance of their respective obligations pursuant to this Lease, shall observe and comply with all
requirements of the CC&R and Development Approvals. The CC&R covers certain areas shown on the site plan attached as
Exhibit K , including landscaping, private drives, streets, parks, open space, walkways, sidewalks, the ice skating rink, the water
fountain, the sky bowl and other improvements and appurtenances located thereon and related thereto, including the Building
and other buildings located on the Property thereon, all commonly referred to as “Kendall Square”, and expenses payable by
the Building under the CC&R (which are based on the Lot’s proportionate share of Kendall Square) are included in Operating
Expenses.
  
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     13.3. Tenant shall be permitted access to the Building and Premises on a 24 hour per day, 7 day per week basis, subject to
matters described in Section 41.6 of this Lease and Landlord’s reasonable security measures, and subject to Landlord’s rights
pursuant to this Lease to temporarily prohibit, restrict or limit access to the Building or the Premises in emergency situations if
Landlord determines, in its reasonable discretion, that it is necessary or advisable to do so in order to prevent or protect against
death or injury to persons or damage to property.

      13.4. It is intended that all Rent payable by Tenant to Landlord, which includes all sums, charges, or amounts of whatever
nature to be paid by Tenant to Landlord in accordance with the provisions of this Lease, shall qualify as “rents from real
property” within the meaning of both Sections 512(b)(3) and 856(d) of the Code and the U.S. Department of Treasury 
Regulations promulgated thereunder (the “Regulations”). If Landlord, in its sole discretion, determines that there is any risk that
all or part of any Rent shall not qualify as “rents from real property” for the purposes of Section 512(b)(3) or 856(d) of the Code 
and the Regulations, Tenant agrees (i) to cooperate with Landlord by entering into such amendment or amendments to this 
Lease as Landlord reasonably deems necessary to qualify all Rent as “rents from real property,” and (ii) to permit an assignment 
of this Lease; provided, however, that any adjustments required under this Section shall be made so as to produce the
substantially equivalent (in economic terms) Rent as payable before the adjustment.

      13.5. (a) Tenant shall have a non-exclusive, irrevocable license to use up to a total of 189 unreserved parking spaces (i.e.,
determined by multiplying the Rentable Area of the Premises by 0.0015) from and after the Phase 1 Rent Commencement Date (“ 
Tenant’s Parking Spaces ”) in the underground parking garage on the Property in common with other tenants of the Property at
the market rate for such comparable parking lots in commercial garages in the East Cambridge market, as reasonably determined
by Landlord (as of the date hereof, such rate being Two Hundred Sixty and 00/100 Dollars ($260.00) per parking space per
month), which Tenant shall pay simultaneously with payments of Base Rent as Additional Rent commencing on the Phase 1
Rent Commencement Date unless and except to the extent that Landlord directs Tenant to pay the same to a Garage Operator as
defined below. Upon 30 days’ notice given prior to the Phase 1 Rent Commencement Date, Tenant will have the option of
designating any number of Tenant’s Parking Spaces between the maximum number set forth above and the portion of Tenant’s
Parking Spaces allocable to the Phase 1 Premises (based on Rentable Area) as being licenses as of the Phase 1 Rent
Commencement Date (with the remainder of Tenant’s Parking Spaces being treated as allocable to the Phase 2 Premises).
Tenant’s failure to make any such election prior to the Phase 1 Premises Rent Commencement Date shall be deemed to be an
election to allocate such spaces on a prorated basis between the Phase 1 Premises and Phase 2 Premises. Tenant shall pay for
the license to use Tenant’s Parking Spaces regardless of whether such spaces are in fact used by Tenant; provided, however,
that Tenant shall have the right to terminate its license with respect to any such spaces on 30 days’ prior written notice to
Landlord. Any such termination of Tenant’s license hereunder in whole or in part shall be irrevocable and Landlord shall have
no further right to provide Tenant with spaces for which such rights have terminated, provided that Landlord shall use
reasonable efforts to make additional spaces available to Tenant, subject to availability, on a revocable, month-to-month
  
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basis as reasonably requested by Tenant on at least 30 days’ prior notice (and otherwise on the terms and conditions contained
in this Section 13.5, including the limitation on total spaces licensed by Tenant set forth above). All of Tenant’s Parking Spaces
shall be located in the underground parking structure in the Building (the “ Garage ”), which Garage may be owned or leased by
or to a third-party Garage operator from time to time. The owner or operator of the Garage from time to time is herein referred to
as the “ Garage Operator ,” and the Tenant’s Parking Spaces are sometimes herein referred to as the “ Garage Parking Spaces .” 
Landlord covenants and agrees that if the Garage is conveyed or leased by Landlord to any Garage Operator, such conveyance
shall be subject to a lease, permanent easement or similar instrument by and between Landlord and the Garage Operator so that
the Tenant shall have, from and after the Phase 1 Rent Commencement Date, throughout the Term, the right to use the Garage
Parking Spaces, subject to the terms of this Lease.

           (b) Landlord or the Garage Operator, as applicable, shall have the right, from time to time but not more often than
every two (2) years, to relocate, on a temporary basis (not to exceed thirty (30) days) as may be necessary to effect repairs and 
improvements to the Garage or for other business reasons, parking spaces located in the Garage to another location within 1,000
feet of the Property. Except to the extent resulting from their negligence or willful misconduct and subject to Section 23.7 ,
neither Landlord nor the Garage Operator shall be responsible for money, jewelry, automobiles or other personal property lost in
or stolen from the Garage, regardless of whether such loss or theft occurs when the Garage or other areas therein are locked or
otherwise secured against entry, or liable for any loss, injury or damage to persons using the Garage or automobiles or other
property therein, it being agreed that the use of the Garage and the Tenant’s Parking Spaces shall otherwise be at the sole risk
of Tenant and its employees, visitors and guests. Landlord and the Garage Operator shall have the right from time to time to
promulgate Rules and Regulations regarding the Garage, the Tenant’s Parking Spaces and the use thereof, including, but not
limited to, Rules and Regulations controlling the flow of traffic to and from various parking areas, the angle and direction of
parking and the like, and to implement valet parking. Tenant shall comply with and cause its employees, visitors and guests to
comply with all such Rules and Regulations as well as reasonable additions and amendments thereto.

          (c) Landlord or the Garage Operator, as applicable, may elect to provide parking cards or keys to control access to the
Garage. In such event, Landlord or the Garage Operator shall provide Tenant with one card or key for each Tenant’s Parking
Space that Tenant is leasing hereunder, provided that Landlord or the Garage Operator shall have the right to require Tenant or
its employees to place a reasonable deposit (not to exceed Twenty-Five Dollars ($25.00)) on such access cards or keys and to
pay a reasonable fee for any lost or damaged cards or keys. Tenant, at its sole cost and expense, may obtain extra cards and
keys from Landlord or the Garage Operator, as applicable, if any cards are lost, stolen or destroyed.

      13.6. Landlord reserves the right to modify the Common Areas, including the right to add or remove exterior and interior
landscaping. Tenant acknowledges that Landlord specifically reserves the right to allow the exclusive use of corridors and
restroom facilities located on specific floors to one or more tenants occupying such floors; provided , however, that Tenant
shall not be deprived of the access to or use of the corridors reasonably required to serve the Premises or of restroom facilities
serving each floor upon which any portion of the Premises is located.
  
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    13.7. Subject to the terms of this Lease including the Rules and Regulations and the rights of other tenants of the Building,
Tenant shall have the non-exclusive right to access the freight loading dock, at no additional cost.

14. Property Control by Landlord .
      14.1. Landlord reserves full control over the Building and Property to the extent not inconsistent with Tenant’s use and
enjoyment of the Premises as provided by this Lease. Subject to the foregoing, this reservation includes Landlord’s right to
convert the Building to a condominium form of ownership; add or eliminate a portion of the Property; grant easements and
licenses to third parties; maintain or establish ownership of the Building separate from fee title to the Property; make additions
to or reconstruct portions of the Building; install, use, maintain, repair, replace and relocate for service to the Premises and other
parts of the Building or the Property pipes, ducts, conduits, wires and appurtenant fixtures, wherever located in the Premises,
the Building or elsewhere at the Property; and alter or relocate any other Common Area or facility, including private drives,
lobbies and entrances. Landlord will use reasonable efforts to ensure that any work undertaken in the Premises by Landlord
shall (except in an emergency) be undertaken in a manner that will not unreasonably interfere with Tenant’s operations.

     14.2. Possession of those existing areas of the Premises necessary for utilities, services, safety and operation of the
Building is reserved to Landlord.

     14.3. Tenant shall, at Landlord’s request, promptly execute such further documents, in form and substance reasonably
acceptable to the parties, as may be reasonably appropriate to assist Landlord in the performance of its obligations hereunder;
provided that Tenant need not execute any document that creates additional liability for Tenant or that deprives Tenant of the
quiet enjoyment and use of the Premises as provided for in this Lease.

      14.4. Landlord may, at any and all reasonable times during non-business hours (or during business hours, if (a) with 
respect to Subsections 14(u) through 14.4(y) , Tenant so requests, and (b) with respect to Subsection 14.4(z) , if Landlord so
requests), and upon twenty-four (24) hours’ prior notice ( provided that no time restrictions shall apply or advance notice be
required if an emergency necessitates immediate entry), enter the Premises to (u) inspect the same and to determine whether 
Tenant is in compliance with its obligations hereunder, (v) supply any service Landlord is required to provide hereunder, 
(w) alter, improve or repair any portion of the Building other than the Premises for which access to the Premises is reasonably 
necessary,(x) post notices of nonresponsibility, (y) access the telephone equipment, electrical substation and fire risers and 
(z) show the Premises to prospective and actual lenders, purchasers or, during the final year of the Term, tenants. In connection 
with any such alteration, improvement or repair as described in Subsection 14.4(w) , Landlord may erect in the Premises or
elsewhere in the Property scaffolding and other structures reasonably required for the alteration, improvement or repair work to
be performed. Notwithstanding anything to the contrary set forth herein, neither Landlord, nor Landlord’s agents,
representatives, contractors or employees may enter any portion of the Premises reasonably designated from time to time by
Tenant as a
  
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security area (not to exceed 35,000 square feet of Rentable Area in the aggregate, consisting of up to 25,000 square feet of
Rentable Area for a vivarium and up to 10,000 square feet of Rentable Area for a data center) without being accompanied by a
representative of Tenant, except in the case of an emergency, provided that such areas are clearly labeled as such and Landlord
is given at least 10 business days’ prior written notice of the location of such areas. In no event shall Tenant’s Rent abate as a
result of Landlord’s activities pursuant to this Section; provided , however, that all such activities shall be conducted in such a
manner so as to cause as little interference to Tenant as is reasonably possible. Landlord shall at all times retain a key with
which to unlock all of the doors in the Premises. If an emergency necessitates immediate access to the Premises, Landlord may
use whatever force is necessary to enter the Premises, and any such entry to the Premises shall not constitute a forcible or
unlawful entry to the Premises, a detainer of the Premises, or an eviction of Tenant from the Premises or any portion thereof.

15. Quiet Enjoyment . So long as Tenant is not in Default under this Lease, Landlord or anyone acting through or under
Landlord shall not disturb Tenant’s use or occupancy of the Premises or the exercise of Tenant’s rights hereunder in
accordance with this Lease, except as permitted by this Lease.

16. Utilities and Services .
      16.1. Tenant shall pay for all water (including the cost to service, repair and replace reverse osmosis, de-ionized and other
treated water), gas, heat, light, power, telephone, internet service, cable television, other telecommunications and other utilities
supplied to the Premises, together with any fees, surcharges and taxes thereon. Tenant shall, promptly after the Term
Commencement Date as part of the Tenant Improvements, install separate meters, or if separate direct metering is not possible,
sub- or check- meters for any such utilities provided to the Premises (other than those utilities that are used to supply Landlord
services, which are included in Operating Expenses). If any such utility is separately metered, Tenant shall pay the charge
therefore directly to the utility service provider when due. If any such utility is sub- or check-metered from time to time, then
Tenant shall pay for all such charges based on Landlord’s reading of such sub- or check-meters within 30 days after invoice. If,
notwithstanding the foregoing, any such utility is not separately or sub- or check-metered from time to time, then Tenant shall
pay to Landlord within 30 days after invoice for such charges based on Tenant’s Share of such charges provided to the
Building, or Landlord may, at its option, monitor the usage of such utilities by Tenant and charge Tenant with the cost of
purchasing, installing and monitoring such metering equipment, which cost shall be paid by Tenant as Additional Rent. At any
time that Tenant is paying Landlord for the foregoing utilities based on Tenant’s Share, Landlord shall have the right to require
Tenant to pay 1/12th of Landlord’s reasonable estimate of such charges for the applicable calendar year during the term on a
monthly basis, together with payments of Base Rent, and shall reconcile such payments annually. To the extent that Tenant
uses more than Tenant’s Pro Rata Share of the Building of any utilities and such utilities are not separately metered or
submetered, then Tenant shall pay Landlord for Tenant’s Share of such utilities to reflect such excess. In the event that the
Building is less than fully occupied and Tenant is not then separately metered or sub- or check-metered for any utility, Tenant
acknowledges that Landlord may extrapolate utility usage that varies depending on the occupancy of the Building, by dividing
(a) the total cost of utility usage by (b) the Rentable Area of the Lab Building that is occupied, then multiplying (y) the resulting 
quotient by (z) ninety-five
  
                                                                 22
percent (95%) of the total Rentable Area of the Lab Building. Tenant shall pay Tenant’s Share of the product of (y) and (z), 
subject to adjustment based on actual usage as reasonably determined by Landlord; provided , however, that Landlord shall
not recover more than one hundred percent (100%) of such utility costs. 

       16.2. Landlord shall not be liable for, nor shall any eviction of Tenant or default of Landlord result from, the failure to
furnish any utility or service, regardless of the cause, including accident; breakage; strike, lockout or other labor disturbance or
labor dispute of any character; act of terrorism; shortage of materials, which shortage is not unique to Landlord or Tenant, as
the case may be; failure by a third party to deliver gas, oil or another suitable fuel supply; or Landlord’s inability by exercise of
reasonable diligence to obtain gas, oil or another suitable fuel; governmental regulation, moratorium or other governmental
action, inaction or delay; or other causes described in Section 41.6 of this Lease or Landlord’s negligence. In the event of such
failure, Tenant shall not be entitled to termination of this Lease or any abatement or reduction of Rent, nor shall Tenant be
relieved from the operation of any covenant or agreement of this Lease. Notwithstanding anything to the contrary in this Lease,
if, for more than five (5) consecutive business days following written notice to Landlord and, for any reason other than matters 
described in Section 41.6 of this Lease or by an act or omission in violation of this Lease by Tenant or by any negligence of any 
of Tenant’s agents, employees, contractors, invitees, successors or others using the Premises with Tenant’s expressed or
implied permission, the provision of elevator, HVAC, plumbing, or utilities to all or a material portion of the Premises that
Landlord must provide pursuant to this Lease is interrupted, then Tenant’s Base Rent and Operating Expenses (or, to the extent
that less than all of the Premises are affected, a proportionate amount (based on the Rentable Area of the Premises that is
rendered unusable) of Base Rent and Operating Expenses) shall thereafter be abated until the Premises are again usable by
Tenant for the Permitted Use (and the Property Management Fee shall be reduced for such period to reflect any such reduction
in Base Rent); provided , however, that, if Landlord provides substitute elevator, HVAC, plumbing or utilities reasonably
suitable for Tenant’s continued use and occupancy of the Premises for the Permitted Use (e.g., supplying potable water or
portable air conditioning equipment), then neither Base Rent nor Operating Expenses shall be abated so long as Landlord is
diligently pursuing the restoration of such elevator, HVAC, plumbing or utilities. In the event of any interruption of elevator,
HVAC, plumbing, or other utilities that Landlord must provide pursuant to this Lease, regardless of the cause, Landlord shall
diligently pursue the restoration of such elevator, HVAC, plumbing, or other utilities. Notwithstanding anything in this Lease to
the contrary, but subject to Article 24 (which shall govern in the event of a casualty), so long as Landlord is diligently pursuing
the restoration, the provisions of this Section shall be Tenant’s sole recourse and remedy in the event of an interruption of
utilities or Landlord services to the Premises.

     16.3. Tenant shall pay for, prior to delinquency of payment therefor, any services that may be furnished to the Premises
during or, if Tenant occupies the Premises after the expiration or earlier termination of the Term, after the Term, beyond those
services provided by Landlord, including telephone, internet service, cable television and other telecommunications, together
with any fees, surcharges and taxes thereon. Tenant shall pay for such services directly to the supplier of such services.
  
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     16.4. Tenant shall not, without Landlord’s prior written consent, which shall not be unreasonably withheld, delayed or
conditioned, use any device in the Premises (including data processing machines) that will in any way (a) increase the amount 
of ventilation, air exchange, gas, steam, electricity or water required or consumed in the Premises based upon Tenant’s Pro Rata
Share of the Building beyond the existing capacity of the Building usually furnished or supplied for the use set forth in
Section 2.7 or (b) exceed Tenant’s Pro Rata Share of the Building’s capacity to provide such utilities or services.

      16.5. If Tenant shall require utilities or services in excess of those usually furnished or supplied for tenants in similar
spaces in the Building or the Property by reason of Tenant’s equipment or extended hours of business operations, then Tenant
shall first procure Landlord’s consent for the use thereof, which consent Landlord may condition upon the availability of such
excess utilities or services, and Tenant shall pay as Additional Rent an amount equal to Landlord’s actual cost (as may be
reasonably estimated by Landlord) of providing such excess utilities and services to the extent not otherwise paid by Tenant
pursuant to the provisions of Section 16.1, above. 

    16.6. Landlord shall provide water in Common Areas for lavatory and landscaping purposes only, which water shall be
from the local municipal or similar source. Tenant shall not use or consume water provided to the Common Areas for any
purpose other than ordinary or reasonable lavatory purposes.

      16.7. Subject to the provisions of Section 16.2, above, Landlord reserves the right to stop service of the elevator, plumbing, 
HVAC and other utility systems for reasonable periods when Landlord reasonably deems necessary or desirable due to
accident, emergency or the need to make repairs, alterations or improvements, until such repairs, alterations or improvements
shall have been completed. Landlord shall use reasonable efforts to schedule and perform any such repairs, alterations or
improvements outside of business hours to the extent the same will adversely affect Tenant’s ability to conduct its business in
the Premises.

      16.8. Subject to the provisions of this Lease governing Alterations, Tenant, at its sole cost and expense, shall have the
appurtenant right to install and maintain, at no additional charge, one emergency generator, together with connections to
existing Building fuel piping to serve the same (collectively, the “ Generator ”) serving the Premises as reasonably required for
Tenant’s operations in the Premises, subject to Landlord’s reasonable approval with respect to specifications of such generator
and the plans for such installation, in a location within the Rooftop Installation Area or in the Garage as may be mutually agreed
upon between Landlord and Tenant. Tenant shall be responsible for obtaining and maintaining, at its sole cost and expense,
any permits or approvals required in connection with the installation and maintenance of the Generator. The Generator shall be
screened from view in a manner consistent with the standards for a first class office, laboratory and research and development
park in Kendall Square. The installation of the Generator shall be in compliance with applicable laws, codes and ordinances and
shall not interfere with or compromise the integrity of the Building.
  
  
                                                                 24
     16.9. Landlord shall maintain and operate the Building HVAC systems and shall permit Tenant to connect to the same at
the Premises points of connection for Tenant’s use within the Premises and shall furnish HVAC to the Common Areas for
reasonably comfortable occupancy of the same throughout the term of this Lease. To the extent that Tenant requires HVAC
services in excess of those provided by connection to the Building HVAC systems, Tenant shall install and maintain
supplemental HVAC systems in accordance with the provisions of this Lease.

      16.10. For any utilities serving the Premises for which Tenant is billed directly by such utility provider, Tenant agrees to
furnish to Landlord (a) any invoices or statements for such utilities, (b) any other utility usage information received by Tenant 
and reasonably requested by Landlord, and (c) any ENERGY STAR® Statement of Performance (or similar comprehensive utility
usage report (e.g., related to Labs 21), if requested by Landlord) and any other information reasonably requested by Landlord
for the immediately preceding year, all within ninety (90) days after Landlord’s request made no more often than one (1) time per 
year. Tenant shall retain records of utility usage at the Premises, including invoices and statements from the utility provider, for
at least sixty (60) months, or such shorter period of time as may be requested by Landlord. Tenant acknowledges that any utility 
information for the Premises, the Building and the Property may be shared with third parties, including Landlord’s consultants
and Governmental Authorities.

     16.11. Tenant shall have 24-hour access to the freight elevator and freight loading dock serving the Premises in common
with other tenants of the Building at no additional cost (other than to the extent includable in Operating Expenses) and shall
have the right, in common with others, to use the passenger elevators in the Building.

17. Alterations .
      17.1. Tenant shall make no alterations, additions or improvements other in or to the Premises or engage in any
construction, demolition, reconstruction, renovation, or other work (whether major or minor) of any kind in, at, or serving the
Premises (“ Alterations “, which shall include Tenant Improvements) without Landlord’s prior written approval, which approval
Landlord shall not unreasonably withhold, condition or delay; provided , however, that in the event any proposed Alteration
adversely affects (a) any structural portions of the Building, including exterior walls, roof, foundation, foundation systems 
(including barriers and subslab systems), or core of the Building, (b) the exterior of the Building or (c) other than in a minor 
manner not adversely affecting the same, any Building systems, including elevator, plumbing, air conditioning, heating,
electrical, security, life safety and power, then Landlord may withhold its approval with respect thereto in its sole and absolute
discretion. Tenant shall, in making any such Alterations, use only those architects, contractors, suppliers and mechanics of
which Landlord has given prior written approval, which approval shall not be unreasonably withheld, delayed or conditioned. In
seeking Landlord’s approval, Tenant shall provide Landlord, at least fourteen (14) days in advance of any proposed 
construction, with plans, specifications, stamped engineering drawings and calculations by Tenant’s engineer of record or
architect or record, certified as being in accordance with Applicable Laws (including connections to the Building’s structural
system, modifications to the Building’s envelope, non-structural penetrations in slabs or walls, and modifications or tie-ins to
life safety systems), work contracts, requests for laydown areas and such other information concerning the nature and cost of
the Alterations as Landlord may reasonably request. In no event shall Tenant use or Landlord be required to approve any
architects, consultants, contractors, subcontractors or material
  
                                                                25
suppliers that Landlord reasonably believes is likely to cause labor disharmony. Landlord may condition its approval of any
Alterations on Tenant’s removing the same upon the expiration or earlier termination of this Lease or Tenant’s right to
possession of the Premises, at Tenant’s sole cost, provided that Landlord so notifies Tenant at the time that Landlord approves
the plans for such Alterations. Notwithstanding the foregoing, Tenant may make non-structural minor and cosmetic changes to
the Premises (“ Cosmetic Alterations ”) without Landlord’s consent; provided that (y) the cost of any Cosmetic Alterations do 
not exceed Fifty Thousand Dollars ($50,000) in any one instance, (z) such Cosmetic Alterations do not (i) require any structural 
or other substantial modifications to the Premises, (ii) require any changes to, or adversely affect, the Building systems, 
(iii) affect the exterior of the Building or (iv) trigger any requirement under Applicable Laws that would require Landlord to make 
any alteration or improvement to the Building or the Property. Tenant shall give Landlord at least ten (10) days’ prior written
notice of any Cosmetic Alterations.

      17.2. Tenant shall not construct or permit to be constructed partitions or other obstructions that are likely to unreasonably
interfere with free access to mechanical installation or service facilities of the Building or with other tenants’ components
located within the Building, or interfere with the moving of Landlord’s equipment to or from the enclosures containing such
installations or facilities.

     17.3. Tenant shall accomplish any work performed on the Premises or the Building in such a manner as to permit any life
safety systems to remain fully operable at all times.

     17.4. Any work performed on the Premises, the Building or the Property by Tenant or Tenant’s contractors shall be done at
such times and in such manner as Landlord may from time to time reasonably designate. Tenant covenants and agrees that all
work done by Tenant or Tenant’s contractors shall be performed in full compliance with Applicable Laws. Within thirty
(30) days after completion of any Alterations (other than Cosmetic Alterations), Tenant shall provide Landlord with complete 
“as-built” drawing print sets, project specifications and shop drawings, and electronic CADD files on disc (or files in such other
current format in common use as Landlord reasonably approves or requires) showing any changes in the Premises. Any such
“as-built” plans shall show the applicable Alterations as an overlay on the Building as-built plans, to the extent provided by
Landlord to Tenant for such purpose.

    17.5. Before commencing any Alterations, Tenant shall give Landlord at least fourteen (14) days’ prior written notice of the
proposed commencement of such work and shall, if requested by Landlord for any Alterations costing more than $200,000,
when taken together with any related Alterations being made as part of the same project, secure, at Tenant’s own cost and
expense, a performance, completion and lien indemnity bond reasonably satisfactory to Landlord for such work.

      17.6. Tenant shall repair any damage to the Premises caused by Tenant’s removal of any property from the Premises at the
expiration or earlier termination of the Term. The provisions of this Section shall survive the expiration or earlier termination of
this Lease.

     17.7. (a) The Premises shall at all times remain the property of Landlord and shall be surrendered to Landlord upon the
expiration or earlier termination of this Lease.
  
                                                                 26
           (b) All Alterations, Signage, attached equipment, decorations, fixtures, movable laboratory casework and related
appliances, trade fixtures, additions and improvements attached to or built into the Premises, made by either of the Parties
(including all floor and wall coverings, built-in cabinet work and paneling, sinks and related plumbing fixtures, laboratory
benches, exterior venting fume hoods and walk-in freezers and refrigerators, ductwork, conduits, electrical panels and circuits),
shall (unless, prior to such construction or installation, Landlord in writing elects otherwise) become the property of Landlord
upon the expiration or earlier termination of the Term, and shall remain upon and be surrendered with the Premises as a part
thereof.

          (c) Subject to Section 17.7(b) and except as to those items listed on Exhibit G attached hereto (which Exhibit G may be
updated by Tenant from and after the Term Commencement Date, subject to Landlord’s written consent), all Alterations,
together with all additions and accessories thereto, installed in and upon the Premises shall be and remain the property of
Landlord and shall not be moved by Tenant at any time during the Term.

          (d) Notwithstanding any other provision of this Article to the contrary, in no event shall Tenant remove any
improvement from the Premises as to which Landlord contributed payment, including the Tenant Improvements, without
Landlord’s prior written consent, which consent Landlord may withhold in its sole and absolute discretion. Landlord may
require Tenant to remove Specialty Alterations prior to the expiration or earlier termination of the Term; provided, however, that
Tenant shall not be required to remove any Specialty Alterations to the extent the same are shown on Exhibit B-2 attached
hereto. For purposes of this Lease, “ Specialty Alterations ” shall mean Alterations that are not consistent with standard office
or laboratory installations.

           (e) If Tenant shall fail to remove any of its effects from the Premises prior to termination of this Lease, then Landlord
may, at its option, remove the same in any manner that Landlord shall choose and store such effects without liability to Tenant
for loss thereof or damage thereto, and Tenant shall pay Landlord, upon demand, any costs and expenses incurred due to such
removal and storage or Landlord may, at its sole option and without notice to Tenant, sell such property or any portion thereof
at private sale and without legal process for such price as Landlord may obtain and apply the proceeds of such sale against any
(i) amounts due by Tenant to Landlord under this Lease and (ii) any expenses incident to the removal, storage and sale of such 
personal property.

     17.8. Other than with respect to the Tenant Improvements, Tenant shall pay to Landlord an amount equal to three percent
(3%) of the cost to Tenant of all Alterations (other than Tenant Improvements and Cosmetic Alterations) to cover Landlord’s
overhead and expenses for plan review, coordination, scheduling and supervision thereof. For purposes of payment of such
sum, Tenant shall submit to Landlord copies of all bills, invoices and statements covering the costs of such charges,
accompanied by payment to Landlord of the fee set forth in this Section. To the extent Tenant does not perform such remedial
work within a reasonable time after notice from Landlord, and if Landlord thereafter performs the same, Tenant shall reimburse
Landlord for any extra expenses actually incurred by Landlord by reason of faulty work done by Tenant or its contractors, or by
reason of delays caused by such work, or by reason of inadequate clean-up.
  
                                                                 27
     17.9. Within sixty (60) days after final completion of any Alterations performed by Tenant with respect to the Premises, 
Tenant shall submit to Landlord documentation showing the amounts expended by Tenant with respect to such Alterations,
together with supporting documentation reasonably acceptable to Landlord.

     17.10. Tenant shall take, and shall cause its contractors to take, commercially reasonable steps to protect the Premises
during the performance of any Alterations, including covering or temporarily removing any window coverings so as to guard
against dust, debris or damage.

     17.11. Tenant shall require its contractors and subcontractors performing work on the Premises to name the Landlord
Parties and Lenders as additional insureds on their respective general liability insurance policies.

18. Repairs and Maintenance .
     18.1. Landlord shall repair and maintain in good condition the structural and exterior portions and Common Areas of the
Building and the Property, including roofing and covering materials; foundations; exterior walls; plumbing; fire sprinkler
systems (if any); heating, ventilating, air conditioning systems; elevators; and electrical systems installed or furnished by
Landlord consistent with other similar properties in the rental market in which the Building is located, and in full accordance
with Applicable Laws applicable to office and laboratory use generally, without regard for Tenant’s Alterations. The Common
Areas shall be maintained by Landlord in compliance with the ADA except to the extent such compliance would not be required
but for Tenant’s Alterations or its particular use of the Premises, as opposed to the Permitted Uses, generally. Landlord shall
maintain (or provide for the maintenance of) in a neat, attractive and first-class condition all signs, roadways, landscaped areas,
parking areas, sidewalks and entrances areas on the Property.

     18.2. Except for services of Landlord, if any, required by Section 18.1 , Tenant shall at Tenant’s sole cost and expense
maintain and keep the Premises and every part thereof in good condition and repair, excepting damage thereto from ordinary
wear and tear, and damage by casualty or condemnation (except to the extent Tenant is obligated to restore the same) excepted.
Tenant shall, upon the expiration or sooner termination of the Term, surrender the Premises to Landlord in as good a condition
as when received, excepting damage thereto from ordinary wear and tear, and damage by casualty or condemnation (except to
the extent Tenant is obligated to restore the same), and matters for which Tenant is not responsible; and shall, at Landlord’s
request and Tenant’s sole cost and expense, remove all telephone and data systems, wiring and equipment from the Premises,
and repair any damage to the Premises caused thereby. Landlord shall have no obligation to alter, remodel, improve, repair,
decorate or paint the Premises or any part thereof, other than as described in Exhibit B . Tenant shall be responsible, at its sole
cost and expense, for the cleaning of the Premises and Tenant’s removal of its trash, garbage and Hazardous Materials;
provided, however, that Tenant is encouraged to participate in the waste removal and recycling program in place at the
Property. Landlord shall provide a dumpster at the loading dock for Tenant’s use in the disposal of materials (other than
Hazardous Materials and other controlled substances).
  
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      18.3. Landlord shall not be liable for Claims arising out of any failure to make any repairs or to perform any maintenance
that is Landlord’s obligation pursuant to this Lease unless such failure shall persist for an unreasonable time after Tenant
provides Landlord with written notice of the need of such repairs or maintenance (or unless Landlord has actual knowledge of
the need therefor). Tenant waives its rights under Applicable Laws now or hereafter in effect to make repairs at Landlord’s
expense; however, in the event that Landlord fails to make a repair or perform maintenance that is Landlord’s obligation
pursuant to this Lease within applicable notice and cure periods set forth in Section 31.11, and such failure continues for ten 
(10) days after notice thereof to Landlord (with a copy to Landlord’s mortgagee) or such shorter period, if any, as may be
feasible in case of an emergency threatening life or property (such notice to expressly state in bold and prominent print
Tenant’s intention to exercise its rights under this Section), then Tenant, without being under any obligation to do so and
without thereby waiving such default, may remedy such default and perform such repair for the account and at the expense of
Landlord. All reasonable expenditures made by Tenant in connection therewith, including reasonable attorneys’ fees in
instituting, prosecuting or defending any action or proceeding, shall be paid to Tenant by Landlord within thirty (30) days after 
submission by Tenant to Landlord of a reasonably detailed invoice therefor. If Landlord fails to pay such costs to Tenant within
fifteen (15) days following notice from Tenant of such failure, then Tenant shall have the right to recover the same by an 
abatement of Base Rent and the Property Management Fee, provided that such abatement (and the accrual of any interest on
such amounts) shall cease at such time as and to the extent that payment is tendered to Tenant. Notwithstanding the foregoing,
if the amount of the abatement is more than 25% of the aggregate amount of Base Rent due in any month, then the amount
abated in any one month shall not exceed 25% of the Base Rent and the excess amount of the abatement shall be carried forward
with interest at the Default Rate. Tenant’s self-help rights under this paragraph shall be exercised by Tenant only (a) with 
respect to conditions actually existing within the Premises and (b) with respect to conditions that materially affect Tenant’s
ability to use and enjoy the Premises and to conduct Tenant’s operations therein. The provisions of this paragraph may not be
exercised by or on behalf of any subtenants. Any disputes regarding Tenant’s right to have undertaken any such remedy, the
amount of reimbursement claimed by Tenant, or the amount of abatement shall be resolved by arbitration as set forth below.

      The parties shall direct the Boston office of the AAA to appoint an arbitrator who shall have a minimum of ten (10) years’ 
experience in commercial real estate disputes and who shall not be affiliated with either Landlord or Tenant and has not worked
for either party or its affiliates at any time during the prior five (5) years. Both Landlord and Tenant shall have the opportunity 
to present evidence and outside consultants to the arbitrator.

     The arbitration shall be conducted in accordance with the expedited commercial arbitration rules of the AAA insofar as
such rules are not inconsistent with the provisions of this Lease (in which case the provisions of this Lease shall govern). The
cost of the arbitration (exclusive of each party’s witness and attorneys’ fees, which shall be paid by such party) shall be borne
equally by the parties. Any such arbitration shall be commenced within ten (10) days after demand (or, if later, appointment of 
the arbitrator).
  
                                                                 29
     Within ten (10) days after appointment, the arbitrator shall determine whether Tenant was entitled to exercise its self-help
rights and/or the amount of reimbursement to which Tenant is entitled. The arbitrator’s decision shall be final and binding on
the parties.

     18.4. If any excavation shall be made upon land adjacent to or under the Building, or shall be authorized to be made, then at
reasonable times and upon reasonable advance notice, Tenant shall afford to the person causing or authorized to cause such
excavation, license to enter the Premises for the purpose of performing such work as such person shall deem necessary or
desirable to preserve and protect the Building from injury or damage and to support the same by proper foundations, without
any claim for damages or liability against Landlord and without reducing or otherwise affecting Tenant’s obligations under this
Lease. Such work will be done at Landlord’s sole cost, and Landlord shall take such measures as are reasonably and
customarily required to avoid any adverse impacts on Tenant’s use and occupancy of the Premises.

    18.5. This Article relates to repairs and maintenance arising in the ordinary course of operation of the Building and the
Property. In the event of a casualty described in Article 24 , Article 24 shall apply in lieu of this Article. In the event of eminent
domain, Article 25 shall apply in lieu of this Article.

     18.6. Costs incurred by Landlord pursuant to this Article shall constitute Operating Expenses (unless otherwise limited or
excluded under Article 9).

19. Liens .
     19.1. Subject to the immediately succeeding sentence, Tenant shall keep the Premises, the Building and the Property free
from any liens arising out of work performed, materials furnished or obligations incurred by Tenant. Tenant further covenants
and agrees that any mechanic’s lien filed against the Premises, the Building or the Property for work claimed to have been done
for, materials claimed to have been furnished to, or obligations incurred by Tenant shall be discharged or bonded by Tenant
within fifteen (15) days after the filing thereof, at Tenant’s sole cost and expense.

      19.2. Should Tenant fail to discharge or bond against any lien of the nature described in Section 19.1 , Landlord may, at
Landlord’s election, pay such claim or post a bond or otherwise provide security to eliminate the lien as a claim against title, and
Tenant shall immediately reimburse Landlord for the costs thereof as Additional Rent. Tenant shall indemnify, save, defend (at
Landlord’s option and with counsel reasonably acceptable to Landlord) and hold the Landlord Indemnitees harmless from and
against any Claims arising from any such liens, including any administrative, court or other legal proceedings related to such
liens.

      19.3. In the event that Tenant leases or finances the acquisition of office equipment, furnishings or other personal property
of a removable nature utilized by Tenant in the operation of Tenant’s business, Tenant warrants that any Uniform Commercial
Code financing statement shall, upon its face or by exhibit thereto, indicate that such financing statement is applicable only to
removable personal property of Tenant located within the Premises. In no event shall the address of the Premises, the Building
or the Property be furnished on a financing statement without qualifying language as to applicability of the lien only to
removable personal property
  
                                                                  30
located in an identified suite leased by Tenant. Should any holder of a financing statement record or place of record a financing
statement that appears to constitute a lien against any interest of Landlord or against equipment that may be located other than
within an identified suite leased by Tenant, Tenant shall, within ten (10) days after filing such financing statement, cause (a) a 
copy of the Lender security agreement or other documents to which the financing statement pertains to be furnished to
Landlord to facilitate Landlord’s ability to demonstrate that the lien of such financing statement is not applicable to Landlord’s
interest and (b) Tenant’s Lender to amend such financing statement and any other documents of record to clarify that any liens
imposed thereby are not applicable to any interest of Landlord in the Premises, the Building or the Property. Landlord will, on
request by Tenant, execute and deliver any reasonable waiver or subordination of Landlord’s lien that may be required in
connection with any such financing, provided the same does not amend the provisions of this Lease and is reasonably
acceptable to Landlord. Tenant shall be responsible for, and shall reimburse Landlord for, all reasonable attorneys’ fees incurred
by Landlord in connection with any such request.

20. Estoppel Certificate . (a) Tenant shall, within ten (10) business days of receipt of written notice from Landlord, execute, 
acknowledge and deliver a statement in writing substantially in the form attached to this Lease as Exhibit I , or on any other form
reasonably requested by a proposed Lender or purchaser, (a) certifying that this Lease is unmodified and in full force and effect 
(or, if modified, stating the nature of such modification and certifying that this Lease as so modified is in full force and effect)
and the dates to which rental and other charges are paid in advance, if any, (b) acknowledging that there are not, to Tenant’s
knowledge, any uncured defaults on the part of Landlord hereunder, or specifying such defaults if any are claimed, and
(c) setting forth such further factual information with respect to this Lease or the Premises as may be reasonably requested 
thereon. Any such statement may be relied upon by any prospective purchaser or encumbrancer of all or any portion of the real
property of which the Premises are a part. Tenant’s failure to deliver such statement within such the prescribed time, if such
failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which notice shall state, in bold 
and prominent print, that failure to reply shall result in a Default under this Section 21(a)), shall, at Landlord’s option, constitute
a Default (as defined below) under this Lease and, in any event, shall be binding upon Tenant that this Lease is in full force and
effect and without modification except as may be represented by Landlord in any certificate prepared by Landlord and delivered
to Tenant for execution. However, no such certificate shall have the effect of amending this Lease, and in the case of any
conflict between this Lease and any certificate, this Lease shall prevail.

           (b) Landlord shall, within ten (10) business days of receipt of written notice from Tenant, execute, acknowledge and 
deliver a statement in writing (a) certifying that this Lease is unmodified and in full force and effect (or, if modified, stating the 
nature of such modification and certifying that this Lease as so modified is in full force and effect) and the dates to which rental
and other charges are paid in advance, if any, (b) acknowledging that there are not, to Landlord’s knowledge, any uncured
defaults on the part of Tenant hereunder, or specifying such defaults if any are claimed, and (c) setting forth such further 
factual information with respect to this Lease or the Premises as may be reasonably requested thereon. However, no such
certificate shall have the effect of amending this Lease, and in the case of any conflict between this Lease and any certificate,
this Lease shall prevail.
  
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21. Hazardous Materials .
      21.1. Tenant shall not cause or permit any Hazardous Materials (as defined below) to be brought upon, kept or used in or
about the Premises, the Building or the Property in violation of Applicable Laws by Tenant or its employees, agents,
contractors or invitees. If Tenant breaches such obligation, or if the presence of Hazardous Materials as a result of such a
breach results in contamination of the Property, any portion thereof, or any adjacent property, or if contamination of the
Premises otherwise occurs during the Term or any extension or renewal hereof or holding over hereunder (other than if such
contamination results from migration of Hazardous Materials from outside the Premises not caused by Tenant or its employees,
agents, contractors or invitees), then Tenant shall indemnify, save, defend (at Landlord’s option and with counsel reasonably
acceptable to Landlord) and hold the Landlord Indemnitees harmless from and against any and all Claims that arise during or
after the Term as a result of such breach or contamination. This indemnification by Tenant includes costs incurred in
connection with any investigation of site conditions or any clean-up, remedial, removal or restoration work required by any
Governmental Authority because of Hazardous Materials present in the air, soil or groundwater above, on or under or about the
Property. Without limiting the foregoing, if the presence of any Hazardous Materials in, on, under or about the Property, any
portion thereof or any adjacent property caused or permitted by Tenant results in any contamination of the Property, any
portion thereof or any adjacent property, then Tenant shall promptly take all actions at its sole cost and expense as are
necessary to return the Property, any portion thereof or any adjacent property to its respective condition existing prior to the
time of such contamination; provided that Landlord’s written approval of such action shall first be obtained, which approval
Landlord shall not unreasonably withhold; and provided , further, that it shall be reasonable for Landlord to withhold its
consent if such actions could have a material adverse long-term or short-term effect on the Property, any portion thereof or any
adjacent property. Notwithstanding any provision of this Lease to the contrary, Tenant shall in no event have any liability (by
way of indemnification or otherwise) for removal or remediation of any Hazardous Materials from the Premises or the Property to
the extent (i) of any condition existing in, on or under the Premises or the Property, as the case may be, on the Term 
Commencement Date, (ii) related to Hazardous Materials that migrate to the Premises following the Term Commencement Date 
from some other part of the Building or Property other than as a result of the acts or omissions of Tenant or any Tenant Party,
or (iii) placed or release in or on the Premises following the Term Commencement Date by Landlord or Landlord’s agents,
contractors and employees.

      21.2. Landlord acknowledges that it is not the intent of this Article to prohibit Tenant from operating its business for the
Permitted Use. Tenant may operate its business according to the custom of Tenant’s industry so long as the use or presence of
Hazardous Materials is strictly and properly monitored in accordance with Applicable Laws. As a material inducement to
Landlord to allow Tenant to use Hazardous Materials in connection with its business, Tenant agrees to deliver to Landlord
(a) so-called MSDS sheets identifying each type of Hazardous Material to be present at the Premises that is subject to
regulation under any environmental Applicable Laws, (b) a list of any and all approvals or permits from Governmental 
Authorities required in connection with the presence of such Hazardous Material at the Premises and (c) correct and complete 
copies of (i) written notices of violations of Applicable Laws actually received by Tenant related to Hazardous Materials at the 
Premises and (ii) plans relating to the installation of any storage tanks to be installed in, on, under or about the Property 
( provided that
  
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installation of storage tanks shall only be permitted after Landlord has given Tenant its written consent to do so, which consent
Landlord may withhold in its reasonable discretion with respect to above-ground storage tanks, and its sole and absolute
discretion with respect to underground storage tanks, if any) and closure plans or any other documents required by any and all
Governmental Authorities for any storage tanks installed in, on, under or about the Property for the closure of any such storage
tanks (collectively, “ Hazardous Materials Documents ”). Tenant shall deliver to Landlord updated Hazardous Materials
Documents (l) no later than thirty (30) days prior to the initial occupancy of any portion of the Premises or the initial placement 
of equipment anywhere at the Property, (m) if there are any changes to the Hazardous Materials Documents, annually thereafter 
no later than December 31 of each year, and (n) thirty (30) days prior to the initiation by Tenant of any Alterations or changes in 
Tenant’s business that involve any material increase in the types or amounts of Hazardous Materials. For each type of
Hazardous Material listed, the Hazardous Materials Documents shall include (t) the chemical name, (u) the material state (e.g., 
solid, liquid, gas or cryogen), (v) the concentration, (w) the storage amount and storage condition (e.g., in cabinets or not in 
cabinets), (x) the use amount and use condition (e.g., open use or closed use), (y) the location (e.g., room number or other 
identification) and (z) if known, the chemical abstract service number. Notwithstanding anything in this Section to the contrary, 
Tenant shall not be required to provide Landlord with any Hazardous Materials Documents containing information of a
proprietary nature, which Hazardous Materials Documents, in and of themselves, do not contain a reference to any Hazardous
Materials or activities related to Hazardous Materials. Landlord may, at Landlord’s expense, cause the Hazardous Materials
Documents to be reviewed by a person or firm qualified to analyze Hazardous Materials to confirm compliance with the
provisions of this Lease and with Applicable Laws. In the event that a review of the Hazardous Materials Documents indicates
non-compliance with this Lease or Applicable Laws, Tenant shall, at its expense, diligently take steps to bring its storage and
use of Hazardous Materials into compliance. Notwithstanding anything to the contrary herein, in no event shall Tenant
generate, produce, bring upon, use, store or treat Hazardous Materials with a risk category higher than Biosafety Level 2 as 
established by the Department of Health and Human Services (“ DHHS ”) and as further described in the DHHS publication
Biosafety in Microbiological and Biomedical Laboratories (5th Edition) (as it may be or may have been further revised, the “ 
BMBL ”) or such nationally recognized new or replacement standards as may be reasonably selected by Landlord if applicable
to similar facilities in the City of Cambridge).

     21.3. Notwithstanding the provisions of Sections 21.1 , 21.2 or 21.9 , if any proposed transferee, assignee or sublessee of
Tenant is then subject to an outstanding material enforcement order issued by any Governmental Authority in connection with
the use, disposal or storage of Hazardous Materials, then it shall not be unreasonable for Landlord to withhold its consent to
any proposed transfer, assignment or subletting (with respect to any such matter involving a proposed transferee, assignee or
sublessee).

     21.4. At any time, and from time to time, prior to the expiration of the Term, Landlord shall have the right to conduct
appropriate tests of the Property or any portion thereof to demonstrate that Hazardous Materials are present or that
contamination has occurred due to the acts or omissions of Tenant or Tenant’s employees, agents, contractors or invitees
(provided that such tests shall be conducted in a manner that does not unreasonably interrupt or interfere with Tenant’s use of
the Premises for the Permitted Use). Tenant shall pay all reasonable costs of such tests if such tests reveal that Hazardous
Materials exist at the Property in violation of this Lease.
  
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     21.5. If underground or other storage tanks storing Hazardous Materials installed or utilized by Tenant are located on the
Premises, or are hereafter placed on the Premises by Tenant (or by any other party, if such storage tanks are utilized by Tenant),
then Tenant shall monitor the storage tanks, maintain appropriate records, implement reporting procedures, properly close any
underground storage tanks, and take or cause to be taken all other steps necessary or required under the Applicable Laws.
Tenant shall have no responsibility or liability for underground or other storage tanks installed by anyone other than Tenant
unless Tenant utilizes such tanks, in which case Tenant’s responsibility for such tanks shall be as set forth in this Section.

     21.6. Tenant shall promptly report to Landlord any actual or suspected presence of mold or water intrusion in the Premises.

     21.7. Tenant’s obligations under this Article shall survive the expiration or earlier termination of this Lease. During any
period of time needed by Tenant or Landlord after the termination of this Lease to complete the removal from the Premises of
any such Hazardous Materials, Tenant shall be deemed a holdover tenant and subject to the provisions of Article 27 below.

     21.8. As used herein, the term “ Hazardous Material ” means, but shall not be limited to, any hazardous substances,
hazardous waste, environmental, biological, chemical, radioactive substances, oil, petroleum products and any waste or
substance, which because of its quantitative concentration, chemical, biological, radioactive, flammable, explosive, infectious or
other characteristics, constitutes or may reasonably be expected to constitute or contribute to a danger or hazard to public
health, safety or welfare or to the environment, including without limitation any asbestos (whether or not friable) and any
asbestos-containing materials, lead paint, waste oils, solvents and chlorinated oils, polychlorinated biphenyls (PCBs), toxic
metals, etchants, pickling and plating wastes, explosives, reactive metals and compounds, pesticides, herbicides, radon gas,
urea formaldehyde foam insulation and chemical, biological and radioactive wastes, or any other similar materials that are
regulated by any Governmental Authority.

      21.9. Notwithstanding anything to the contrary in this Lease, Landlord shall have sole control over the equitable allocation
of fire control areas (as defined in the Uniform Building Code as adopted by the city or municipality(ies) in which the Property is
located (the “ UBC ”)) within the Property for the storage of Hazardous Materials; provided that Tenant shall have the
appurtenant right to use its pro-rata share of such fire control areas made available to tenants on any floor of the Premises
(determined on a floor-by-floor basis based on the ratio of the rentable square footage of the Premises on such floor to the total
rentable square footage of leasable area on such floor as reasonably determined by Landlord on a consistent basis), other than
the first floor of the Building if and to the extent the Premises includes any portion of such floor. Notwithstanding anything to
the contrary in this Lease, the quantity of Hazardous Materials allowed by this Section 21.9 is specific to Tenant and shall not
run with the Lease in the event of a Transfer (as defined in Article 29 ). In the event of a Transfer, if the use of
  
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Hazardous Materials by such new tenant (“ New Tenant ”) is such that New Tenant utilizes fire control areas in the Building in
excess of New Tenant’s Pro Rata Share of the Building, then New Tenant shall, at its sole cost and expense and upon
Landlord’s written request, establish and maintain a separate area of the Premises classified by the UBC as an “H” occupancy
area for the use and storage of Hazardous Materials, or take such other action as is necessary to ensure that its share of the fire
control areas of the Building is not greater than New Tenant’s Pro Rata Share of the Building.

22. Odors and Exhaust . Tenant acknowledges that Landlord would not enter into this Lease with Tenant unless Tenant assured
Landlord that under no circumstances will any other occupants of the Building or the Property (including persons legally
present in any outdoor areas of the Property) be subjected to odors or fumes (whether or not noxious), and that the Building
and the Property will not be damaged by any exhaust, in each case from Tenant’s operations. Landlord and Tenant therefore
agree as follows (and Landlord agrees that it will use commercially reasonable efforts to include substantially similar provisions
regarding odors and exhaust in all lease agreements with other office and/or laboratory tenants or occupants of the Building):

     22.1. Tenant shall not cause or permit (or conduct any activities that would cause) any release of any odors or fumes of
any kind inconsistent with typical first-class office and laboratory use from the Premises.

     22.2. If the Building has a ventilation system that, in Landlord’s judgment, is adequate, suitable, and appropriate to vent
the Premises in a manner that does not release odors affecting any indoor or outdoor part of the Property, Tenant shall vent the
Premises through such system. If Landlord at any time determines that any existing ventilation system is inadequate, or if no
ventilation system exists, Tenant shall in compliance with Applicable Laws vent all fumes and odors from the Premises (and
remove odors from Tenant’s exhaust stream) as Landlord reasonably requires. The placement and configuration of all
ventilation exhaust pipes, louvers and other equipment shall be subject to Landlord’s approval. Tenant acknowledges
Landlord’s legitimate desire to maintain the Property (indoor and outdoor areas) in an odor-free manner, and Landlord may
require Tenant to abate and remove all odors in a manner that goes beyond the requirements of Applicable Laws.

     22.3. Tenant shall, at Tenant’s sole cost and expense, provide commercially reasonable levels of odor eliminators and other
devices (such as filters, air cleaners, scrubbers and whatever other equipment may in Landlord’s judgment be reasonably
necessary or appropriate from time to time) to completely remove, eliminate and abate any odors, fumes or other substances in
Tenant’s exhaust stream that emanate from Tenant’s operations in the Premises. Any work Tenant performs under this Section
shall constitute Alterations.

     22.4. Tenant’s responsibility to remove, eliminate and abate odors, fumes and exhaust caused by operations conducted by,
through or under Tenant shall continue throughout the Term. Landlord’s approval of any Alterations shall not preclude
Landlord from requiring additional measures to eliminate odors, fumes and other adverse impacts of Tenant’s exhaust stream (as
Landlord may designate in Landlord’s reasonable discretion). To the extent reasonably necessary to control odors or fumes
caused by operations conducted by, through or under Tenant, Tenant shall install additional equipment as Landlord reasonably
requires from time to time under the preceding sentence. Such installations shall constitute Alterations.
  
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     22.5. If Tenant fails to install satisfactory odor control equipment within thirty (30) days after Landlord’s demand made at
any time (which may include effective temporary measures so long as permanent measures are taken within thirty (30) days 
thereafter), then Landlord may, without limiting Landlord’s other rights and remedies, require Tenant to cease and suspend any
operations in the Premises that, in Landlord’s determination, cause odors, fumes or exhaust. For example, if Landlord determines
that Tenant’s production of a certain type of product causes odors, fumes or exhaust, and Tenant does not install satisfactory
odor control equipment within thirty (30) days after Landlord’s request, then Landlord may require Tenant to stop producing
such type of product in the Premises unless and until Tenant has installed odor control equipment satisfactory to Landlord.

     22.6. In the event that Tenant installs or maintains any small animal facilities in connection with its laboratory operations in
the Premises, Tenant shall construct and maintain a vacuum-enabled disposal facility for bedding waste and any other noxious
wastes (or such other disposal system reasonably acceptable to Landlord that satisfactorily disposes of such wastes and
controls odors). In no event may any such animal facilities exceed 25,000 square feet of Rentable Area within the Premises.

23. Insurance; Waiver of Subrogation .
     23.1. Landlord shall maintain property insurance for the Building and the Property in amounts equal to full replacement
cost (exclusive of the costs of excavation, foundations and footings, and without reference to depreciation taken by Landlord
upon its books or tax returns), providing protection against any peril generally included within the classification “Special Form,” 
together with insurance against sprinkler damage (if applicable), vandalism and malicious mischief and boiler and machinery
coverage. Landlord, subject to availability thereof, shall further insure, if Landlord deems it appropriate, coverage against flood,
environmental hazard, earthquake, loss or failure of building equipment, rental loss during the period of repairs or rebuilding,
workmen’s compensation insurance and fidelity bonds for employees employed to perform services and may carry such other
insurance coverages, and additional amounts, as are prudent in Landlord’s reasonable determination or are required by
mortgagees from time to time.

      23.2. In addition, Landlord shall carry commercial general liability insurance with a combined single limit of not less than
Five Million Dollars ($5,000,000) for death or bodily injury, or property damage with respect to the Property, to be written on an
occurrence basis. Such insurance required to be carried by Landlord shall be with companies authorized to do business in the
state in which the Property is located and having a rating of not less than policyholder rating of “A-” and financial category
rating of at least Class X in “Best’s Insurance Guide.” 

     23.3. Tenant shall, at its own cost and expense, procure and maintain in effect, beginning on the Term Commencement
Date, and continuing throughout the Term (and occupancy by Tenant, if any, after termination of this Lease) commercial
general liability insurance with limits of not less than Five Million Dollars $5,000,000) per occurrence for death or bodily injury
and for property damage with respect to the Premises (including $100,000 fire legal liability (each loss)).
  
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      23.4. The insurance required to be purchased and maintained by Tenant pursuant to this Lease shall name Landlord, BMR-
PR II LLC, BioMed Realty, L.P., BioMed Realty Trust, Inc., The Prudential Insurance Company of America, BioMed Realty LLC,
and their respective officers, directors, employees, agents, general partners, members, subsidiaries, affiliates and Lenders (“ 
Landlord Parties ”) as additional insureds. Such insurance shall be with companies authorized to do business in the state in
which the Property is located and having a rating of not less than policyholder rating of “A-” and financial category rating of at
least Class X in “Best’s Insurance Guide.” No such additional insured coverage shall be required to protect or insure against
loss arising from the negligence or wrongful act or omissions of an additional insured. Tenant shall obtain for Landlord from the
insurance companies or cause the insurance companies to furnish certificates of coverage to Landlord. No such policy shall be
cancelable or subject to material reduction of coverage except after thirty (30) days’ prior written notice to Landlord (except in
the event of non-payment of premium, in which case ten (10) days written notice shall be given). All such policies shall be 
written as primary policies, not contributing with and not in excess of the coverage that Landlord may carry. Tenant’s policy
may be a “blanket policy” that specifically provides that the amount of insurance shall not be prejudiced by other losses
covered by the policy. Tenant shall, no later than ten (10) days following the expiration of such policies, furnish evidence 
reasonably acceptable to Landlord of Tenant’s procurement of replacement insurance. Tenant agrees that if Tenant does not
take out and maintain such insurance, Landlord may (but shall not be required to) procure such insurance on Tenant’s behalf
and at its cost to be paid by Tenant as Additional Rent.

     23.5. Except for matters arising from the negligence or willful misconduct of Landlord or its agents, contractors and
employees (and then subject to Section 23.7), Tenant assumes the risk of damage to any fixtures, goods, inventory, 
merchandise, equipment and leasehold improvements, and Landlord shall not be liable for injury to Tenant’s business or any
loss of income therefrom, relative to such damage, all as more particularly set forth within this Lease. Tenant shall, at Tenant’s
sole cost and expense, carry such insurance as Tenant desires for Tenant’s protection with respect to personal property of
Tenant or business interruption.

     23.6. In each instance where insurance is to name Landlord Parties as additional insureds, Tenant shall, upon Landlord’s
written request, also designate and furnish certificates evidencing such Landlord Parties as additional insureds to (a) any 
Lender of Landlord holding a security interest in the Building or the Property, (b) the landlord under any lease whereunder 
Landlord is a tenant of the Property if the interest of Landlord is or shall become that of a tenant under a ground lease rather
than that of a fee owner and (c) any management company retained by Landlord to manage the Property. 

     23.7. Landlord and Tenant each hereby waive any and all rights of recovery against the other or against the officers,
directors, employees, agents, general partners, members, subsidiaries, affiliates and Lenders of the other on account of loss or
damage occasioned by such waiving party or its property or the property of others under such waiving party’s control, in each
case to the extent that such loss or damage is insured (or required under this Lease to be insured) against under any fire and
extended coverage insurance policy that either Landlord or Tenant
  
                                                                 37
may have in force at the time of such loss or damage. Such waivers shall continue so long as their respective insurers so permit.
Any termination of such a waiver shall be by written notice to the other party, containing a description of the circumstances
hereinafter set forth in this Section. Landlord and Tenant, upon obtaining the policies of insurance required or permitted under
this Lease, shall give notice to the insurance carrier or carriers that the foregoing mutual waiver of subrogation is contained in
this Lease. If such policies shall not be generally obtainable from reputable insurers with such waiver or shall be so obtainable
only at a premium over that chargeable without such waiver, then the party seeking such policy shall notify the other of such
conditions, and the party so notified shall have ten (10) days thereafter to either (a) procure such insurance with companies 
reasonably satisfactory to the other party or (b) agree to pay such additional premium (in Tenant’s case, in the proportion that
the area of the Premises bears to the insured area). If the parties do not accomplish either (a) or (b), then this Section shall have 
no effect during such time as such policies shall not be obtainable or the party in whose favor a waiver of subrogation is
desired refuses to pay the additional premium. If such policies shall at any time be generally unobtainable from reputable
insurers, but shall be subsequently obtainable, then neither party shall be subsequently liable for a failure to obtain such
insurance until a reasonable time after notification thereof by the other party. If the release of either Landlord or Tenant, as set
forth in the first sentence of this Section, shall contravene Applicable Laws, then the liability of the party in question shall be
deemed not released but shall be secondary to the other party’s insurer.

     23.8. Landlord may require insurance policy limits required under this Lease to be raised from time to time to conform with
reasonable requirements of Landlord’s Lender or to bring coverage limits to reasonable levels then being required of other
similar office and laboratory tenants within Kendall Square, generally.

     23.9. Any costs incurred by Landlord pursuant to this Article shall constitute a portion of Operating Expenses to the extent
not otherwise expressly excluded pursuant to the provisions of Section 9.1(c). 

24. Damage or Destruction .
      24.1. In the event of a partial destruction of (a) the Premises or (b) Common Areas of the Building or the Property ((a) and 
(b) together, the “ Affected Areas ”) by fire or other perils covered by special form insurance not exceeding twenty-five percent
(25%) of the full insurable value thereof, and provided that the damage thereto is such that the Affected Areas may be repaired,
reconstructed or restored within a period of one (1) year from the adjustment of such casualty loss with the insurer, and 
Landlord shall receive insurance proceeds sufficient to cover the cost of such repairs, reconstruction and restoration (except for
any commercially reasonable deductible amount provided by Landlord’s policy, which deductible amount, if paid by Landlord,
shall constitute an Operating Expense, and provided that Landlord shall have complied with the requirements of Section 23.1), 
then Landlord shall commence and proceed diligently with the work of repair, reconstruction and restoration of the Affected
Areas and this Lease shall continue in full force and effect. If Landlord does not receive insurance proceeds sufficient to cover
the cost of such repairs, reconstruction and restoration, despite Landlord’s diligent and commercially reasonable efforts, and
neither Landlord nor any Mortgagee has commenced such restoration within three (3) months following 
  
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adjustment of such casualty loss with the insurer, then Tenant may, until any such restoration commences, terminate this Lease
by giving at least thirty (30) days’ prior written notice thereof to Landlord and such termination shall be effective on the date
specified if such replacement has not then commenced.

       24.2. In the event of any damage to or destruction of the Building or the Property other than as described in Section 24.1 ,
Landlord may elect to repair, reconstruct and restore the Building or the Property, as applicable, in which case this Lease shall
continue in full force and effect. If Landlord elects not to repair, reconstruct and restore the Building or the Property, as
applicable, in accordance with Section 24.3, below, then this Lease shall terminate as of the date of such damage or destruction. 
In the event of any damage or destruction (regardless of whether such damage is governed by Section 24.1 or this Section), if
(a) in Landlord’s determination as set forth in the Damage Repair Estimate (as defined below), the Affected Areas cannot be
repaired, reconstructed or restored within twelve (12) months after the date that repairs would commence (provided such 
Damage Repair Estimate is provided to Tenant within 60 days following the date of such damage or destruction), or (b) subject 
to Section 24.6 , the Affected Areas are not actually repaired, reconstructed and restored within the longer of (I) twelve 
(12) months after the date that repairs were to commence as estimated in the Damage Repair Estimate or (II) the period estimated 
for repair as set forth in the Damage Repair Estimate, then Tenant shall have the right to terminate this Lease, effective as of the
date of such damage or destruction, by delivering to Landlord its written notice of termination (a “ Termination Notice ”)
(y) with respect to Subsection 24.2(a) , no later than fifteen (15) days after Landlord delivers to Tenant Landlord’s Damage
Repair Estimate and (z) with respect to Subsection 24.2(b) , no later than fifteen (15) days after such period (as the same may be 
extended pursuant to Section 24.6 ) expires. If Tenant provides Landlord with a Termination Notice pursuant to Subsection 24.2
(z) , Landlord shall have an additional thirty (30) days after receipt of such Termination Notice to complete the repair, 
reconstruction and restoration. If Landlord does not complete such repair, reconstruction and restoration within such thirty
(30) day period, then Tenant may terminate this Lease by giving Landlord written notice within two (2) business days after the 
expiration of such thirty (30) day period. If Landlord does complete such repair, reconstruction and restoration within such 
thirty (30) day period, then this Lease shall continue in full force and effect. If Landlord does not so give a notice of its election 
not to repair, then Landlord shall be deemed to have elected to repair the Property and Premises as aforesaid.

     24.3. As soon as reasonably practicable, but in any event within sixty (60) days following the date of damage or 
destruction, Landlord shall notify Tenant of Landlord’s good faith estimate of the period of time in which the repairs,
reconstruction and restoration will be completed (the “ Damage Repair Estimate ”), which estimate shall be based upon the
opinion of a contractor reasonably selected by Landlord and experienced in comparable repair, reconstruction and restoration of
similar buildings. Additionally, Landlord shall give written notice to Tenant within sixty (60) days following the date of damage 
or destruction of its election not to repair, reconstruct or restore the Building or the Property, as applicable.

      24.4. Upon any termination of this Lease under any of the provisions of this Article, the parties shall be released thereby
without further obligation to the other from the date possession of the Premises is surrendered to Landlord, except with regard
to (a) items occurring prior to the damage or destruction and (b) provisions of this Lease that, by their express terms, survive 
the expiration or earlier termination hereof.
  
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      24.5. In the event of repair, reconstruction and restoration as provided in this Article, all Rent to be paid by Tenant under
this Lease shall be abated proportionately based on the extent to which Tenant’s use of the Premises is impaired during the
period of such repair, reconstruction or restoration (and the Property Management Fee shall be reduced based on such
reduction in Base Rent, if any), unless Landlord provides Tenant with other space during the period of repair, reconstruction
and restoration that, in Tenant’s reasonable opinion, is suitable for the temporary conduct of Tenant’s office and/or laboratory
operations. Tenant acknowledges that, given such abatement, Tenant will not have any claim against its own insurer to recover
rent that would otherwise have been payable during the period of such abatement.

     24.6. Notwithstanding anything to the contrary contained in this Article, should Landlord be delayed or prevented from
completing the repair, reconstruction or restoration of the damage or destruction to the Premises after the occurrence of such
damage or destruction by matters described in Section 41.6 of this Lease or delays caused by Tenant or its employees, agents, 
contractors or invitees, then the time for Landlord to commence or complete repairs, reconstruction and restoration shall be
extended on a day-for-day basis.

      24.7. If Landlord is obligated to or elects to repair, reconstruct or restore as herein provided, then Landlord shall be
obligated to make such repairs, reconstruction or restoration only with regard to (a) those portions of the Premises that were 
originally provided at Landlord’s expense (i.e. excluding Alterations, other than to the extent funded by the TI Allowance) and
(b) the Common Area portion of the Affected Areas. The repairs, reconstruction or restoration of improvements not originally 
provided by Landlord or at Landlord’s expense shall be the obligation of Tenant. Tenant alone shall be entitled to settle, adjust
and receive the proceeds of any insurance policies held by Tenant, and to use the proceeds thereof as Tenant deems
appropriate for the restoration of Tenant’s Alterations. In the event Tenant has elected to upgrade certain improvements from
the Building Standard, Landlord shall, upon the need for replacement due to an insured loss, provide only the Building
Standard, unless Tenant again elects to upgrade such improvements and pay any incremental costs related thereto, except to
the extent that excess insurance proceeds, if received, are adequate to provide such upgrades, in addition to providing for basic
repairs, reconstruction and restoration of the Premises, the Building and the Property.

     24.8. Notwithstanding anything to the contrary contained in this Article, Landlord shall not have any obligation
whatsoever to repair, reconstruct or restore the Premises if the damage resulting from any casualty covered under this Article
occurs during the last twelve (12) months of the Term or any extension thereof, or to the extent that insurance proceeds are not 
available therefor.

    24.9. Landlord’s obligation, should it elect or be obligated to repair, reconstruct or restore, shall be limited to the Affected
Areas. Tenant shall, at its expense, replace or fully repair all of Tenant’s personal property and any Alterations installed by
Tenant existing at the time of such damage or destruction. If Affected Areas are to be repaired, reconstructed or restored in
  
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accordance with the foregoing, Landlord shall make available to Tenant any portion of insurance proceeds it receives that are
allocable to the Alterations constructed by Tenant pursuant to this Lease; provided Tenant is not then in monetary default of
which Tenant shall have received written notice in accordance with this Lease or otherwise in Default under this Lease, and
subject to the reasonable requirements of any Lender of Landlord as to the method of disbursement of such proceeds.

25. Eminent Domain .
     25.1. In the event (a) the whole of all Affected Areas or (b) such part thereof as shall substantially interfere (in Tenant’s
reasonable determination, made in good faith) with Tenant’s reasonable, efficient and beneficial use and occupancy of all or a
substantial portion of the Premises for the Permitted Use shall be taken for any public or quasi-public purpose by any lawful
power or authority by exercise of the right of appropriation, condemnation or eminent domain, or sold to prevent such taking,
Tenant or Landlord may terminate this Lease effective as of the date possession is required to be surrendered to such authority,
except with regard to (y) items occurring prior to the taking and (z) provisions of this Lease that, by their express terms, survive 
the expiration or earlier termination hereof.

     25.2. In the event of a partial taking of (a) the Building or the Property or (b) drives, walkways or parking areas serving the 
Building or the Property for any public or quasi-public purpose by any lawful power or authority by exercise of right of
appropriation, condemnation, or eminent domain, or sold to prevent such taking, then, without regard to whether any portion of
the Premises occupied by Tenant was so taken, Landlord may elect to terminate this Lease (except with regard to (y) items 
occurring prior to the taking and (z) provisions of this Lease that, by their express terms, survive the expiration or earlier 
termination hereof) as of such taking if such taking is, in Landlord’s sole opinion, of a material nature such as to make it
uneconomical to continue use of the unappropriated portion for purposes of renting office or laboratory space.
Notwithstanding the foregoing, Landlord may only exercise its option to terminate this Lease as described in this Section 25.2 if 
Landlord also terminates the leases of tenants similarly affected by such taking.

     25.3. Tenant shall be entitled to any award that is specifically awarded as compensation for (a) the taking of Tenant’s
personal property, trade fixtures and equipment that was installed at Tenant’s expense and (b) the costs of Tenant moving to a 
new location. Except as set forth in the previous sentence, any award for such taking shall be the property of Landlord.

     25.4. If, upon any taking of the nature described in this Article, this Lease continues in effect, then Landlord shall promptly
proceed to restore the Affected Areas to substantially their same condition prior to such partial taking. To the extent such
restoration is infeasible, as determined by Landlord in its reasonable discretion, the Rent shall be decreased proportionately to
reflect the loss of any portion of the Premises no longer available to Tenant (and the Property Management Fee shall be
reduced to reflect any decrease in Base Rent resulting therefrom).
  
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26. Surrender .
      26.1. At least 30 days prior to Tenant’s surrender of possession of any part of the Premises, Tenant shall provide Landlord
with (a) a facility decommissioning and Hazardous Materials closure plan for the Premises (“ Exit Survey ”) prepared by an
independent third party reasonably acceptable to Landlord, (b) written evidence of all appropriate governmental releases 
obtained by Tenant in accordance with Applicable Laws, including laws pertaining to the surrender of the Premises, and
(c) proof that the Premises have been decommissioned in accordance with American National Standards Institute (“ ANSI ”)
Publication Z9.11-2008 (entitled “Laboratory Decommissioning”) or any successor standards published by ANSI or any
successor organization (or, if ANSI and its successors no longer exist, a similar entity publishing similar standards). In addition,
Tenant agrees to remain responsible after the surrender of the Premises for the remediation of any recognized environmental
conditions set forth in the Exit Survey and compliance with any recommendations set forth in the Exit Survey. Tenant’s
obligations under this Section shall survive the expiration or earlier termination of this Lease.

     26.2. No surrender of possession of any part of the Premises shall release Tenant from any of its obligations hereunder,
unless such surrender is accepted in writing by Landlord.

     26.3. The voluntary or other surrender of this Lease by Tenant shall not effect a merger with Landlord’s fee title or
leasehold interest in the Premises, the Building or the Property, unless Landlord consents in writing, and shall, at Landlord’s
option, operate as an assignment to Landlord of any or all subleases.

     26.4. The voluntary or other surrender of any ground or other underlying lease that now exists or may hereafter be
executed affecting the Building or the Property, or a mutual cancellation thereof or of Landlord’s interest therein by Landlord
and its lessor shall not effect a merger with Landlord’s fee title or leasehold interest in the Premises, the Building or the Property
and shall, at the option of the successor to Landlord’s interest in the Building or the Property, as applicable, operate as an
assignment of this Lease.

27. Holding Over .
     27.1. If, with Landlord’s prior written consent, Tenant holds possession of all or any part of the Premises after the Term,
Tenant shall become a tenant from month to month after the expiration or earlier termination of the Term, and in such case
Tenant shall continue to pay (a) Base Rent in accordance with Article 7 , as adjusted in accordance with Article 8 , and (b) any 
amounts for which Tenant would otherwise be liable under this Lease if the Lease were still in effect, including payments for
Tenant’s Share of Operating Expenses. Any such month-to-month tenancy shall be subject to every other term, covenant and
agreement contained herein.

      27.2. Notwithstanding the foregoing, if Tenant remains in possession of the Premises after the expiration or earlier
termination of the Term without Landlord’s prior written consent, (a) Tenant shall become a tenant at sufferance subject to the 
terms and conditions of this Lease, except that the monthly rent shall be equal to one hundred fifty percent (150%) of the Rent 
in effect during the last thirty (30) days of the Term, and (b) Tenant shall be liable to Landlord for any and all damages suffered 
by Landlord as a result of the length of such holdover that exceeds thirty (30) days, including any lost rent or consequential, 
special and indirect damages.
  
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    27.3. Acceptance by Landlord of Rent after the expiration or earlier termination of the Term shall not result in an extension,
renewal or reinstatement of this Lease.

     27.4. The foregoing provisions of this Article are in addition to and do not affect Landlord’s right of reentry or any other
rights of Landlord hereunder or as otherwise provided by Applicable Laws.

28. Indemnification and Exculpation .
      28.1. Except to the extent any matter arises from or as a result of the negligent or willful and wrongful act or omission of
Landlord or its agents, employees or contractors, and subject always to Section 23.7 and 28.2 and any subrogation provisions 
contained in the Work Letter, Tenant agrees to indemnify, save, defend (with counsel reasonably acceptable to Landlord,
unless required to be approved by Tenant’s insurer) and hold the Landlord Indemnitees harmless from and against any and all
Claims arising from injury or death to any person or damage to any property (x) occurring within or about the Premises or, 
(y) arising out of Tenant’s or Tenant’s employees’, agents’, contractors’ or invitees’ negligent or wrongful use or occupancy of
the Building or the Property (other than the Premises). Subject to Sections 23.7 and 28.2 and any subrogation provisions
contained in the Work Letter, Landlord agrees to indemnify, save, defend (at Tenant’s option and with counsel reasonably
acceptable to Tenant) and hold Tenant and its employees, agents and contractors harmless from and against any and all Claims
arising from injury or death to any person or damage to any property occurring within or about the Premises, the Building or the
Property arising out of the gross negligence or willful misconduct of Landlord or its agents, employees or contractors
misconduct.

     28.2. Notwithstanding anything in this Lease to the contrary, unless any such loss is due to the negligent or willful
misconduct of Landlord or its agents, employees or contractors with respect to any repair (or failure to make a repair) that
Landlord is responsible to make for an unreasonable period of time, Landlord shall not be liable to Tenant for and Tenant
assumes all risk of (a) damage or losses caused by fire, electrical malfunction, gas explosion, water damage of any type 
(including broken water lines, malfunctioning fire sprinkler systems, roof leaks or stoppages of lines), and (b) damage to 
personal property. Tenant further waives any claim for injury to Tenant’s business or loss of income relating to any such
damage or destruction of personal property as described in this Section. Notwithstanding anything in the foregoing or this
Lease to the contrary, except (x) as otherwise expressly provided herein, (y) as may be provided by Applicable Laws or (z) in the 
event of Tenant’s breach of Article 21 or Section 26.1 , in no event shall Landlord or Tenant be liable to the other for any
consequential, special or indirect damages arising out of this Lease.

      28.3. Landlord shall not be liable for any damages arising from any act, omission or neglect of any other tenant in the
Building or the Property, or of any other unaffiliated third party (provided that nothing in this Section 28.3 shall be deemed to 
relieve Landlord of its repair and maintenance obligations as set forth in this Lease).

     28.4. Tenant acknowledges that security devices and services, if any, while intended to deter crime, may not in given
instances prevent theft or other criminal acts. Landlord shall not be liable for injuries or losses caused by criminal acts of third
parties, and Tenant assumes the
  
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risk that any security device or service may malfunction or otherwise be circumvented by a criminal. If Tenant desires protection
against such criminal acts, then Tenant shall, at Tenant’s sole cost and expense, obtain appropriate insurance coverage.

     28.5. The provisions of this Article shall survive the expiration or earlier termination of this Lease.

29. Assignment or Subletting .
      29.1. Except as hereinafter expressly permitted, Tenant shall not, either voluntarily or by operation of Applicable Laws,
directly or indirectly sell, hypothecate, assign, pledge, encumber or otherwise transfer this Lease, or sublet the Premises (each, a
“ Transfer ”), without Landlord’s prior written consent. Notwithstanding the foregoing, Tenant shall have the right to Transfer
without Landlord’s prior written consent the Premises or any part thereof to (i) any person that as of the date of determination 
(and is contemplated to so remain), controls, is controlled by, or is under common control with Tenant (“ Tenant’s Affiliate ”),
or (ii) any successor to Tenant by merger, consolidation, acquisition of all or substantially all of Tenant’s assets or ownership
interests, or corporate reorganization, provided that (x) such merger, consolidation, acquisition of all or substantially all of 
Tenant’s assets or ownership interests, or corporate reorganization is for a good business purpose and not principally for the
purpose of transferring this Lease in violation of this provision, (y) the resulting tenant under this Lease has a net worth at least 
equal to or greater than $500,000,000 , and (z) any such successor to Tenant agrees in writing to assume all of the terms, 
covenants and conditions of this Lease arising after the effective date of such assignment (together with Transfers to Tenant’s
Affiliates, “ Exempt Transfers ”). In the event of an Exempt Transfer, Tenant shall notify Landlord in writing at least ten
(10) days prior to the effectiveness of such Exempt Transfer and otherwise comply with the requirements of this Lease regarding 
such Transfer. For purposes of Exempt Transfers, “control” requires both (a) owning (directly or indirectly) more than fifty 
percent (50%) of the stock or other equity interests of another person and (b) possessing, directly or indirectly, the power to 
direct or cause the direction of the management and policies of such person. In no event shall Tenant perform a Transfer (other
than an Exempt Transfer) to or with an entity that is a tenant at the Property or that is in then-active discussions or negotiations
(as evidenced by exchanges of proposals or communications) with Landlord or an affiliate of Landlord to lease premises at the
Property or a property owned by Landlord or an affiliate of Landlord in Kendall Square so long as Landlord or such affiliate has
comparable space available for lease in Kendall Square for a comparable term, as reasonably determined by Landlord.
Notwithstanding anything to the contrary contained in this Section 29.1 , so long as Tenant’s stock is publicly traded on a
nationally recognized exchange, neither a public offering of Tenant’s stock nor the transfer from time to time of Tenant’s stock
over a nationally recognized exchange shall not be deemed a Transfer and shall not require Landlord’s consent.

     29.2. In the event Tenant desires to effect a Transfer, then, at least fifteen (15) but not more than ninety (90) days prior to 
the date when Tenant desires the assignment or sublease to be effective (the “ Transfer Date ”), Tenant shall provide written
notice to Landlord (the “ Transfer Notice ”) containing information (including references) concerning the character of the
proposed transferee, assignee or sublessee; the
  
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Transfer Date; any ownership or commercial relationship between Tenant and the proposed transferee, assignee or sublessee;
and the consideration and all other material terms and conditions of the proposed Transfer, all in such detail as Landlord shall
reasonably require.

      29.3. Landlord, in determining whether consent should be given to a proposed Transfer, may give consideration to (a) the 
financial strength of such transferee, assignee or sublessee (notwithstanding Tenant remaining liable for Tenant’s
performance), and (b) any change in use that such transferee, assignee or sublessee proposes to make in the use of the 
Premises and (c) Landlord’s desire to exercise its rights under Section 29.8 (to the extent applicable) to cancel this Lease. In no
event shall Landlord be deemed to be unreasonable for declining to consent to a Transfer to a transferee, assignee or sublessee
of poor reputation, lacking financial qualifications or seeking a change in the Permitted Use, or jeopardizing directly or indirectly
the status of Landlord or any of Landlord’s affiliates as a Real Estate Investment Trust under the Internal Revenue Code of 1986
(as the same may be amended from time to time, the “ Revenue Code ”). Notwithstanding anything contained in this Lease to
the contrary, (w) no Transfer shall be consummated on any basis such that the rental or other amounts to be paid by the 
occupant, assignee, manager or other transferee thereunder would be based, in whole or in part, on the income or profits
derived by the business activities of such occupant, assignee, manager or other transferee; (x) Tenant shall not furnish or 
render any services to an occupant, assignee, manager or other transferee with respect to whom transfer consideration is
required to be paid, or manage or operate the Premises or any capital additions so transferred, with respect to which transfer
consideration is being paid; (y) Tenant shall not consummate a Transfer with any person in which Landlord owns an interest, 
directly or indirectly (by applying constructive ownership rules set forth in Section 856(d)(5) of the Revenue Code); and 
(z) Tenant shall not consummate a Transfer with any person or in any manner that could cause any portion of the amounts 
received by Landlord pursuant to this Lease or any sublease, license or other arrangement for the right to use, occupy or
possess any portion of the Premises to fail to qualify as “rents from real property” within the meaning of Section 856(d) of the 
Revenue Code, or any similar or successor provision thereto or which could cause any other income of Landlord to fail to
qualify as income described in Section 856(c)(2) of the Revenue Code. 

     29.4. The following are conditions precedent to a Transfer or to Landlord considering a request by Tenant to a Transfer:

          (a) Tenant shall remain fully liable under this Lease during the unexpired Term;

          (b) Tenant shall reimburse Landlord for Landlord’s reasonable and actual third party costs and expenses, including
reasonable attorneys’ fees, charges and disbursements incurred in connection with the review, processing and documentation
of such request;

           (c) If Tenant’s transfer of rights or sharing of the Premises (other than with respect to any Exempt Transfer) provides
for the receipt by, on behalf of or on account of Tenant of any consideration of any kind whatsoever (including a premium
rental for a sublease or lump sum payment for an assignment, but excluding Tenant’s reasonable costs in negotiating the
sublease or assignment and marketing and subleasing the Premises, and in preparing the applicable portion of the Premises for
occupancy by such subtenant or assignee) in excess of the
  
                                                                 45
rental and other charges due to Landlord under this Lease, Tenant shall pay fifty percent (50%) of all of such excess to 
Landlord, after making deductions for any reasonable legal and marketing expenses, tenant improvement funds expended by
Tenant, alterations, architectural/engineering costs, brokerage commissions, attorneys’ fees and free rent actually paid by
Tenant. If such consideration consists of cash paid to Tenant, payment to Landlord shall be made upon receipt by Tenant of
such cash payment;

          (d) The proposed transferee, assignee or sublessee shall agree that, in the event Landlord gives such proposed
transferee, assignee or sublessee notice that Tenant is in Default under this Lease, such proposed transferee, assignee or
sublessee shall thereafter make all payments otherwise due Tenant directly to Landlord, which payments shall be received by
Landlord without any liability being incurred by Landlord, except to credit such payment against those due by Tenant under
this Lease, and any such proposed transferee, assignee or sublessee shall agree to attorn to Landlord or its successors and
assigns should this Lease be terminated for any reason; provided , however, that in no event shall Landlord or its Lenders,
successors or assigns be obligated to accept such attornment;

            (e) Landlord’s consent to any such Transfer shall be effected on Landlord’s reasonable forms;

            (f) Tenant shall not then be in Default hereunder;

            (g) Such proposed transferee, assignee or sublessee’s use of the Premises shall be the same as the Permitted Use;

          (h) Landlord shall not be bound by any provision of any agreement pertaining to the Transfer, except for Landlord’s
written consent to the same;

            (i) Tenant shall pay all transfer and other taxes (including interest and penalties) assessed or payable for any
Transfer;

            (j) Landlord’s consent (or waiver of its rights) for any Transfer shall not waive Landlord’s right to consent to any later
Transfer;

          (k) Tenant shall deliver to Landlord one executed copy of any and all written instruments evidencing or relating to the
Transfer; and

          (l) If such Transferee shall be permitted to engage in any laboratory use, a list of Hazardous Materials (as defined in
Section 21.7 ), certified by the proposed transferee, assignee or sublessee to be true and correct, that the proposed transferee,
assignee or sublessee intends to use or store in the Premises. Additionally, Tenant shall deliver to Landlord, on or before the
date any proposed transferee, assignee or sublessee takes occupancy of the Premises, all of the items relating to Hazardous
Materials of such proposed transferee, assignee or sublessee as described in Section 21.2 .

     29.5. Any Transfer that is not in compliance with the provisions of this Article shall be void and shall, at the option of
Landlord, terminate this Lease. Tenant shall cause each Transferee (including any transferee under an Exempt Transfer), for the
benefit of Landlord, to
  
                                                                  46
reaffirm, on behalf of such Transferee, the representations of, and to otherwise comply with the obligations set forth in,
Section 37, and it shall be reasonable for Landlord to refuse to consent to a Transfer in the absence of such reaffirmation and 
compliance. Tenant agrees that breach of the representations and warranties set forth in Section 37, shall at Landlord’s election
be a default under this Lease for which there shall be no cure.

     29.6. The consent by Landlord to a Transfer shall not relieve Tenant or proposed transferee, assignee or sublessee from
obtaining Landlord’s consent to any further Transfer, nor shall it release Tenant or any proposed transferee, assignee or
sublessee of Tenant from full and primary liability under this Lease.

     29.7. Notwithstanding any Transfer, Tenant shall remain fully and primarily liable for the payment of all Rent and other
sums due or to become due hereunder, and for the full performance of all other terms, conditions and covenants to be kept and
performed by Tenant. The acceptance of Rent or any other sum due hereunder, or the acceptance of performance of any other
term, covenant or condition thereof, from any person or entity other than Tenant shall not be deemed a waiver of any of the
provisions of this Lease or a consent to any Transfer.

      29.8. If Tenant delivers to Landlord a Transfer Notice indicating a desire to transfer this Lease to a proposed transferee,
assignee or sublessee (other than with respect to any Exempt Transfer or sublets not exceeding the lesser of one full floor and
40% of the Premises in the aggregate) for at least 85% of the then remaining term (in the case of a sublease), then Landlord shall
have the option, exercisable by giving notice to Tenant at any time within ten (10) days after Landlord’s receipt of such Transfer
Notice, to terminate (in each case (a) as of the date specified in the Transfer Notice as the Transfer Date, and (b) except for 
those provisions that, by their express terms, survive the expiration or earlier termination hereof) this Lease (y) in its entirety, if 
such Transfer Notice relates to an assignment of this Lease or a sublease of 80% or more of the Premises, or (z) solely with 
respect to the portion of the Premises subject to such Transfer Notice, if such Transfer Notice relates to a sublease of less than
80% of the Premises but at least one full floor of the Building. If Landlord exercises such option, then Tenant shall have the
right to withdraw such Transfer Notice by delivering to Landlord written notice of such election within five (5) business days 
after Landlord’s delivery of notice electing to exercise Landlord’s option to terminate this Lease. In the event Tenant withdraws
the Transfer Notice as provided in this Section, this Lease shall continue in full force and effect in its entirety. No failure of
Landlord to exercise its option to terminate this Lease shall be deemed to be Landlord’s consent to a proposed Transfer. If this
Lease shall be terminated or released as to a portion of the Premises only pursuant to clause (z), above, Base Rent, the Property
Management Fee, Tenant’s Pro Rata Share and the number of parking spaces for Tenant’s use, shall be readjusted
proportionately according to the ratio that the Rentable Area in the portion of the Premises surrendered compares to the
Rentable Area of Tenant’s remaining Premises, and Landlord and Tenant shall enter into a suitable and mutually acceptable
amendment to this Lease reflecting the same.

     29.9. If Tenant sublets the Premises or any portion thereof, Tenant hereby irrevocably authorizes Landlord, during the
continuance of a Default, to collect rent from any such subletting (and upon notice any subtenant shall pay directly to
Landlord) and apply the net amount collected toward Tenant’s obligations under this Lease.
  
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30. Subordination and Attornment .
      30.1. Tenant agrees that this Lease and the rights of Tenant hereunder will be subject and subordinate to any lien of the
holder of any present or future mortgage, and to the rights of any lessor under any ground or improvements lease of the
Building (all mortgages and ground or improvements leases of any priority are collectively referred to in this Lease as
“Mortgage,” and the holder or lessor thereof from time to time as a “ Mortgagee ”), and to all advances and interest thereunder
and all modifications, renewals, extensions and consolidations thereof; provided that any subordination of this Lease shall be
conditioned upon Landlord delivering to Tenant a written, recordable subordination, non-disturbance and attornment
agreement (“ SNDA ”) from the Mortgagee seeking to have this Lease subordinated to its interest substantially in the form
attached as Exhibit J (or in such other commercially reasonable form as may be reasonably acceptable to the parties to such
agreement). Landlord represents and warrants that the only mortgage to which this Lease is subject as of the execution date is
that certain mortgage to Wells Fargo Bank, NA (the “ Existing Mortgagee ”). Landlord shall provide to Tenant, within 30 days
after the date of this Lease, an executed SNDA from the Existing Mortgagee.

      30.2. Notwithstanding the foregoing, Tenant shall execute and deliver upon demand such further reasonable instrument or
instruments as may be reasonably acceptable to the parties to such agreement evidencing such subordination of this Lease to
the lien of any such mortgage or mortgages or lease in which Landlord is tenant as may be reasonably required by Landlord. If
any such Mortgagee so elects, however, this Lease shall be deemed prior in lien to any such lease or mortgage upon or
including the Premises regardless of date and Tenant shall execute a statement in writing to such effect at Landlord’s request.
Tenant’s failure to execute any document required from Tenant under this Section within ten (10) business days after written 
request therefor, if such failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which 
notice shall state, in bold and prominent print, that failure to reply shall result in a Default under this Section 20.2), shall be a 
Default for which this Lease may be terminated without further notice.

      30.3. In the event any proceedings are brought for foreclosure, or in the event of the exercise of the power of sale under
any mortgage or deed of trust made by Landlord covering the Premises, Tenant shall at the election of the purchaser at such
foreclosure or sale attorn to the purchaser upon any such foreclosure or sale and recognize such purchaser as Landlord under
this Lease, so long as such purchaser recognizes Tenant as the tenant under this Lease and all of its rights hereunder, including
this Article.

     30.4. If from time to time Landlord assigns this Lease or the rents payable hereunder to any Mortgagee, whether such
assignment is conditional in nature or otherwise, such assignment shall not be deemed an assumption by the assignee of any
obligations of Landlord; the assignee shall be responsible only for non-performance of Landlord’s obligations that occur after it
succeeds to, and only during the period it holds possession of, Landlord’s interest in the Premises after foreclosure or
voluntary deed in lieu of foreclosure.
  
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31. Defaults and Remedies .
      31.1. Late payment by Tenant to Landlord of Rent and other sums due shall cause Landlord to incur costs not
contemplated by this Lease, the exact amount of which shall be extremely difficult and impracticable to ascertain. Such costs
include processing and accounting charges and late charges that may be imposed on Landlord by the terms of any mortgage or
trust deed covering the Premises. Therefore, if any installment of Rent due from Tenant is not received by Landlord within five
(5) business days after the date such payment is due, Tenant shall pay to Landlord (a) an additional sum of six percent (6%) of 
the overdue Rent as a late charge (provided that, with respect to the first late payment in any twelve (12) month period, no such 
late charge shall be due), plus (b) interest at an annual rate (the “ Default Rate ”) equal to the lesser of (a) twelve percent 
(12%) and (b) the highest rate permitted by Applicable Laws. The parties agree that this late charge represents a fair and 
reasonable estimate of the costs that Landlord shall incur by reason of late payment by Tenant and shall be payable as
Additional Rent to Landlord due with the next installment of Rent or within five (5) business days after Landlord’s demand,
whichever is earlier. Landlord’s acceptance of any Additional Rent (including a late charge or any other amount hereunder)
shall not be deemed an extension of the date that Rent is due or prevent Landlord from pursuing any other rights or remedies
under this Lease, at law or in equity.

     31.2. No payment by Tenant or receipt by Landlord of a lesser amount than the Rent payment herein stipulated shall be
deemed to be other than on account of the Rent, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as Rent be deemed an accord and satisfaction, and Landlord may accept such check or
payment without prejudice to Landlord’s right to recover the balance of such Rent or pursue any other remedy provided in this
Lease or in equity or at law. If a dispute shall arise as to any amount or sum of money to be paid by Tenant to Landlord
hereunder, Tenant shall have the right to make payment “under protest,” such payment shall not be regarded as a voluntary
payment, and there shall survive the right on the part of Tenant to institute suit for recovery of the payment paid under protest.

      31.3. If Tenant fails to pay any sum of money required to be paid by it hereunder, or shall fail to perform any other act on
its part to be performed hereunder, in each case within the applicable notice and cure period (if any) described in Section 31.4 ,
then Landlord may, without waiving or releasing Tenant from any obligations of Tenant, but shall not be obligated to, make
such payment or perform such act; provided that such failure by Tenant unreasonably interfered with the use of the Building or
the Property by any other tenant or with the efficient operation of the Building or the Property, or resulted or could have
resulted in a violation of Applicable Laws or the cancellation of an insurance policy maintained by Landlord. Notwithstanding
the foregoing, in the event of an emergency, Landlord shall have the right to enter the Premises upon such notice as is
reasonable under the circumstances, and act in accordance with its rights as provided elsewhere in this Lease. In addition to the
late charge described in Section 31.1 , Tenant shall pay to Landlord as Additional Rent all sums so paid or incurred by Landlord,
together with interest at the Default Rate, computed from the date such sums were paid or incurred.

     31.4. The occurrence of any one or more of the following events shall constitute a “ Default ” hereunder by Tenant:

          (a) Tenant abandons the Premises;
  
                                                                49
           (b) Tenant fails to make any payment of Rent, as and when due, or to satisfy its obligations under Article 19 , where
such failure shall continue for a period of five (5) Business Days after written notice thereof from Landlord to Tenant; 

          (c) Tenant fails to observe or perform any obligation or covenant contained herein (other than described in
Subsections 31.4(a) and 31.4(b) ) to be performed by Tenant, where such failure continues for a period of thirty (30) days after 
written notice thereof from Landlord to Tenant; provided that, if the nature of Tenant’s default is such that it reasonably
requires more than thirty (30) days to cure, Tenant shall not be deemed to be in Default if Tenant commences such cure within 
such period and thereafter diligently prosecute the same to completion;

              (d) Tenant makes an assignment for the benefit of creditors;

          (e) A receiver, trustee or custodian is appointed to or does take title, possession or control of all or substantially all of
Tenant’s assets and is not removed within 60 days;

          (f) Tenant files a voluntary petition under the United States Bankruptcy Code or any successor statute (as the same
may be amended from time to time, the “ Bankruptcy Code ”) or an order for relief is entered against Tenant pursuant to a
voluntary or involuntary proceeding commenced under any chapter of the Bankruptcy Code;

           (g) Any involuntary petition is filed against Tenant under any chapter of the Bankruptcy Code and is not dismissed
within sixty (60) days; 

              (h) Tenant fails to deliver an estoppel certificate in accordance with Article 20 ; or

          (i) Tenant’s interest in this Lease is attached, executed upon or otherwise judicially seized and such action is not
released within sixty (60) days of the action. 

                 Notices given under this Section shall specify the alleged default and shall demand that Tenant perform the
provisions of this Lease or pay the Rent that is in arrears, as the case may be, within the applicable period of time, or quit the
                                                   BMR-650 E KENDALL B LLC,
Premises. No such notice shall be deemed a forfeiture or a termination of this Lease unless Landlord elects otherwise in such
                                                a Delaware limited liability company

                                                                    and

                                                   AVEO PHARMACEUTICALS, INC.,
                                                       a Delaware corporation


                                                         TABLE OF CONTENTS
  
                                                                                                                                   Page  

1.        Lease of Premises                                                                                                            1  
2.        Basic Lease Provisions                                                                                                       2  
2.        Basic Lease Provisions                                                   2  
3.        Term                                                                     5  
4.        Possession and Commencement Date                                         5  
5.        Condition of Premises                                                    7  
6.        Rentable Area                                                            7  
7.        Rent                                                                     7  
8.        Rent Adjustments                                                         8  
9.        Operating Expenses                                                       8  
10.    Taxes on Tenant’s Property                                                  13  
11.    Security Deposit                                                            14  
12.    Use                                                                         15  
13.    Rules and Regulations, CC&Rs, Parking Facilities and Common Areas           18  
14.    Property Control by Landlord                                                21  
15.    Quiet Enjoyment                                                             22  
16.    Utilities and Services                                                      22  
17.    Alterations                                                                 25  
18.    Repairs and Maintenance                                                     28  
19.    Liens                                                                       30  
20.    Estoppel Certificate                                                        31  
21.    Hazardous Materials                                                         32  
22.    Odors and Exhaust                                                           35  
23.    Insurance; Waiver of Subrogation                                            36  
24.    Damage or Destruction                                                       38  
25.    Eminent Domain                                                              41  
26.    Surrender                                                                   42  
27.    Holding Over                                                                42  
28.    Indemnification and Exculpation                                             43  
29.    Assignment or Subletting                                            44  
30.    Subordination and Attornment                                        48  
31.    Defaults and Remedies                                               49  
  
                                                i


                                       TABLE OF CONTENTS
                                           (continued)
  
                                                                       Page  

32.    Bankruptcy                                                          53  
33.    Brokers                                                             54  
34.    Definition of Landlord                                              54  
35.    Limitation of Liability                                             55  
36.    Joint and Several Obligations                                       56  
37.    Representations                                                     56  
38.    Confidentiality                                                     57  
39.    Notices                                                             57  
40.    Rooftop Installation Area                                           57  
41.    Miscellaneous                                                       59  
42.    Options to Extend Term                                              61  
43.    Right of First Offer                                                62  
44.    Right of First Refusal                                              64  
  
                                                ii


                                       TABLE OF DEFINITIONS
  
                                                                         Page  
Accountant                                     12  
ADA                                            17  
Additional Rent                                 7  
Affected Areas                                 38  
Alterations                                    25  
ANSI                                           42  
Applicable Laws                    3, 5, 8, 9, 10  
Available ROFO Premises                        63  
Available ROFR Premises                        64  
Bankruptcy Code                                50  
Base Rent                                       3  
Baseball Arbitrator                            61  
BMBL                                           33  
Broker                                         54  
Building                                        1  
CC&R                                           18  
Claims                                         17  
Common Area                                     1  
Cosmetic Alterations                           26  
Damage Repair Estimate                         39  
Default                                        49  
Default Rate                                   49  
DHHS                                           33  
Discount Rate                                  51  
Execution Date                                  1  
Exempt Transfers                               44  
Existing Mortgagee                             48  
Exit Survey                                    42  
FMV                                            61  
Garage                                         20  
Garage Operator                                20  
Garage Parking Spaces                          20  
Generator                                      24  
Governmental Authority                          8  
Hazardous Material                             32  
Hazardous Materials Documents                  33  
HVAC                                            5  
Independent Review                             11  
L/C Security                                   14  
Land                                            1  
Landlord                                    1, 54  
Landlord Delay                                  6  
Landlord Indemnitees                          17  
Landlord Indemnitees                                                            17  
Landlord Parties                                                                37  
  
                                                   iii


                                          TABLE OF DEFINITIONS
                                               (continued)
  
                                                                            Page  

Lease                                                                            1  
Lender                                                                          17  
Mortgagee                                                                       48  
MWRA                                                                            18  
New Tenant                                                                      35  
Notice of Marketing                                                             63  
Notice of Offer                                                                 64  
OFAC                                                                            56  
Operating Expenses                                                               8  
Option                                                                          61  
Option Notice                                                                   61  
Phase 1 Premises                                                                 5  
Phase 1 Premises Deadline                                                        5  
Phase 1 Premises Rent Commencement Date                                          5  
Phase 1 Premises Tenant Improvements                                             5  
Phase 2 Premises                                                                 5  
Phase 2 Premises Rent Commencement Date                                          5  
Phase 2 Premises Tenant Improvements                                             5  
Premises                                                                         1  
Property                                                                         1  
Property Management Fee                                                         11  
Property Operations Agreements                                                  18  
REBA                                                                            61  
REFA                                                                            61  
Revenue Code                                                                    45  
ROFO                                                                            63  
ROFR                                                                            64  
ROFR                                                         64  
Rooftop Installation Area                                    57  
Rules and Regulations                                        18  
Security Deposit                                             14  
Signage                                                      16  
SNDA                                                         48  
Specialty Alterations                                        27  
Substantial Completion                                        6  
Substantially Complete                                        6  
Tenant                                                        1  
Tenant Improvements                                           6  
Tenant Premises Notice                                        2  
Tenant’s Affiliate                                           44  
Tenant’s Parking Spaces                                      19  
Tenant’s Rooftop Equipment                                   58  
Tenant’s Share                                               10  
Term                                                          5  
Term Expiration Date                                          5  
Termination Notice                                           39  
  
                                      iv


                             TABLE OF DEFINITIONS
                                  (continued)
  
                                                         Page  

TI Allowance                                                  6  
TI Deadline                                                   6  
Transfer                                                     44  
Transfer Date                                                44  
Transfer Notice                                              44  
UBC                                                          34  
Work Letter                                                   6  
  
                                      v


                                    LEASE
                                                                LEASE

     THIS LEASE (this “ Lease ”) is entered into as of this 9th day of May, 2012 (the “ Execution Date ”), by and between BMR-
650 E Kendall B LLC, a Delaware limited liability company (“ Landlord ”), and AVEO Pharmaceuticals, Inc., a Delaware
corporation (“ Tenant ”).

                                                              RECITALS

     A. WHEREAS, Landlord owns certain real property commonly known as Parcel B and described further on Exhibit A-1
attached hereto (the “ Land ”) and the improvements on the Property located at 650 East Kendall Street, Cambridge,
Massachusetts, including the building and the Garage (as defined in Section 13.5) (collectively, the “Building”) in which the
Premises (as defined below) are located; and

     B. WHEREAS, Landlord wishes to lease to Tenant, and Tenant desires to lease from Landlord, certain premises (the “ 
Premises ”) located on a portion of the fourth (4th) floor, and the entire fifth (5th) and sixth (6th) floors, together with certain off-
floor mechanical areas, of the Building, pursuant to the terms and conditions of this Lease, as detailed below.


                                                            AGREEMENT

     NOW, THEREFORE, Landlord and Tenant, in consideration of the mutual promises contained herein and for other good
and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and intending to be legally bound,
agree as follows:

1. Lease of Premises .
      1.1. Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord, the Premises, as shown on Exhibit A
attached hereto for use by Tenant in accordance with the Permitted Use (as defined below) and no other uses. The Building,
Land and all landscaping, parking facilities, private drives and other improvements and appurtenances located thereon and
related thereto, including the Building and other buildings located on the Land, are hereinafter collectively referred to as the “ 
Property .” All portions of the Building and Property that are for the non-exclusive use of the tenants of the Property, such as
service corridors, elevators, loading docks, public restrooms, public entranceways, lobbies and stairways, electric and
telephone closets (other than those exclusively serving the Premises, if any), janitor closets, and other areas from time to time
designated as common areas by Landlord (all to the extent located in the Building or on the Property) are hereinafter referred to
as “ Common Area .” The Premises exclude Common Areas, fan rooms, mechanical rooms, elevators wells, pipes, ducts,
conduits, wires and appurtenant fixtures serving other parts of the Property (exclusively or in common), and any exterior walls
(including without limitation the roof and roof system) and structural members of the Building. If the Premises include less than
the entire rentable area of any floor, then the Premises also exclude the common corridors, elevator lobby and toilets located on
such floor.


    Tenant shall have the right, on or before to June 1, 2012, in each case by written notice (a “ Tenant Premises Notice ”) to
Landlord identifying the alternative demising of the Premises proposed by Tenant, to (x) reduce or expand the portion of the 
Premises located on the fourth floor by adjusting the location of the demising walls between the Premises and contiguous
Premises located on the fourth floor by adjusting the location of the demising walls between the Premises and contiguous
leaseable areas on the fourth floor by an amount not to exceed five thousand (5,000) square feet of Rentable Area, provided that 
the remainder of the leaseable areas on the fourth floor are readily leaseable for multi-tenant purposes in a first class office and
laboratory building, as reasonably determined by Landlord; there is no adverse impact on Building systems or structure as a
result of such adjustment; and/or (y) substitute alternative, existing off-floor mechanical locations in the Building for the off-
floor mechanical portions of the Premises, provided that such areas are, in Landlord’s reasonable determination, of an
equivalent aggregate Rentable Area, do not impose an inequitable allocation or use of similar mechanical spaces for tenant
spaces in the Building, do not reduce any leaseable areas of the Building, and do not adversely affect Building operations or
access. Within 10 days following the giving of a Tenant Premises Notice, Landlord shall approve the proposed revised Premises
or disapprove such proposal with specific reasons therefor. Landlord’s failure to respond within such ten day period shall be
deemed approval by Landlord. Following the adjustment of the Premises in accordance with this Section, the parties shall enter
into an amendment to this Lease substituting the revised Premises plans for the applicable floors of the Premises for the
Premises plans initially attached as Exhibit A hereto, and the annual Base Rent, Tenant’s Parking Spaces, and Tenant’s Pro Rata
Share (as each term is defined below) shall be adjusted accordingly based on the change in Rentable Area of the Premises as
determined by Landlord in accordance with Article 6, below.

2. Basic Lease Provisions . For convenience of the parties, certain basic provisions of this Lease are set forth herein. The
provisions set forth herein are subject to the remaining terms and conditions of this Lease and are to be interpreted in light of
such remaining terms and conditions.

     2.1. This Lease shall take effect upon the Execution Date and, except as specifically otherwise provided within this Lease,
each of the provisions hereof shall be binding upon and inure to the benefit of Landlord and Tenant from the date of execution
and delivery hereof by all parties hereto.

    2.2. In the definitions below, each current Rentable Area (as defined below) is expressed in rentable square footage.
Rentable Areas and “ Tenant’s Pro Rata Shares ” are all subject to adjustment only as expressly provided in this Lease.
  
                                                                             Means the Following (As of the
                     Definition or Provision                                       Execution Date)
                     Rentable Area of Premises                                  126,065 square feet
                     Rentable Area of Building                                  291,498 square feet
                     Rentable Area of Lab Building                              278,736 square feet
                     Tenant’s Pro Rata Share of Building                             43.25%
                     Tenant’s Pro Rata Share of Lab Building                         45.23%
  
                                                                 2


   2.3. Initial monthly and annual installments of Base Rent for the Premises (“ Base Rent ”) as of the Phase 1 Premises Rent
Commencement Date (as defined in Section 4.1 below), subject to adjustment under this Lease:
  
  
                                                                                             Base Rent per 
                                                                  Square Feet of             Square Foot of 
                                                                  Rentable Area             Rentable Area of      Monthly Base          Annual Base
Dates                                                            for the Premises             the Premises           Rent                  Rent       
Phase 1 Premises Rent Commencement Date – the date                          126,065         $54.50 annually         $572,545.21        $6,870,542.50  
  immediately preceding the first (1 st ) anniversary of
  the Phase 1 Premises Rent Commencement Date                                                                                       

     As further described in Section 4.1, below, Base Rent shall be prorated for the Premises between the Phase 1 and Phase 2 
Premises, and only payable with respect to the Phase 1 Premises, until such time as the Phase 2 Premises Rent Commencement
Date occurs.

     2.4. Term Commencement Date: The date upon which Landlord delivers the Premises to Tenant in its “as is” condition as
of the date hereof with a temporary demising wall constructed on the 4th floor of the Building that is reasonably sufficient for
Tenant to secure such portion of the Premises, which date Landlord shall cause to occur no later than May 31, 2012. 

        2.5. Estimated Term Expiration Date: December 31, 2024. 

        2.6. Security Deposit: $2,862,726.

     2.7. Permitted Use: Office and laboratory use in conformity with all federal, state, municipal and local laws, codes,
ordinances, rules and regulations of Governmental Authorities (as defined below), committees, associations, or other regulatory
committees, agencies or governing bodies having jurisdiction over the Premises, the Building, the Property, Landlord or Tenant,
including both statutory and common law and hazardous waste rules and regulations (“ Applicable Laws ”). Tenant shall obtain
validation by any medical review board or other similar governmental licensing of the Premises required for the Permitted Use.
  
                                                                        3


                     2.8. Address for Rent Payment:                      BMR-650 E Kendall B LLC

                                                                         Pursuant   to the following wire instructions:
                                                                         Name of beneficiary: BMR-650 E Kendall B LLC
                                                                         Account number: 153495105154
                                                                         Bank Name: US Bank
                                                                         Routing/Transit #: 122235821
                                                                         Branch Name & Address: San Diego Main
                                                                         600 W Broadway #100
                                                                         San Diego, CA 92101

                     2.9. Address for Notices to Landlord:               BMR-650 E Kendall B LLC
                                                                17190 Bernardo Center Drive
                                                                San Diego, California 92128
                                                                Attn: Vice President, Real Estate   Counsel
                 2.10. Address for Notices to Tenant:           

                 Prior to the Rent Commencement Date:           AVEO Pharmaceuticals, Inc.
                                                                75 Sidney Street
                                                                Cambridge, MA 02139
                                                                Attn: Chief Financial Officer

                 On or after the Rent Commencement Date:      At the Premises
                 With a copy to:                                Langer & McLaughlin,   LLP
                                                                855 Boylston Street
                                                                Boston, MA 02116


                 2.11. The following Exhibits are attached hereto and incorporated herein by reference:
  
                         Exhibit A        Premises
                         Exhibit A-1      Land
                         Exhibit B        Work Letter
                         Exhibit B-1       Scope of Landlord’s Demising Work
                         Exhibit C        Acknowledgement of Rent Commencement     Date and Term Expiration Date
                         Exhibit D        Development Approvals
                         Exhibit E        Form of Letter of Credit
                         Exhibit F        Rules and Regulations
                         Exhibit G        Tenant’s Personal Property
                         Exhibit H        Form of Estoppel Certificate
                         Exhibit I        SNDA
                         Exhibit J        Rooftop Installation Area
                         Exhibit K        Kendall Square
                         Exhibit L        Tenant’s Signage Location
  
                                                                   4


3. Term . The actual term of this Lease (as the same may be extended pursuant to Article 42 hereof, and as the same may be
earlier terminated in accordance with this Lease, the “ Term ”) shall commence on the Term Commencement Date and end on the
date that is twelve (12) years after the actual Phase 1 Premises Rent Commencement Date (such date, the “ Term Expiration Date
”), subject to earlier termination of this Lease as provided herein, provided that if the Phase 1 Premises Rent Commencement
Date is not the first day of a calendar month, then the Term Expiration Date shall be the last day of the calendar month in which
the twelfth (12 th ) anniversary of the Phase 1 Premises Rent Commencement Date occurs. 

4. Possession and Commencement Date .
      4.1. Landlord has delivered to Tenant, broom clean and free of occupants, and Tenant has accepted possession of, the
Premises as of the date hereof. Landlord represents and warrants to Tenant that, as of the date hereof, the heating, ventilation
and air-conditioning (“HVAC”), electrical, life safety and plumbing systems of the Building are in good working condition and,
to the best of Landlord’s knowledge, not in violation of Applicable Laws applicable to office and laboratory use, generally.
Tenant shall undertake its Tenant Improvements and occupy the Premises for the conduct of its business in two phases. The “ 
Phase 1 Premises ” shall consist of not less than twenty thousand (20,000) square feet of Rentable Area on the sixth (6th) floor 
of the Building identified by Tenant to Landlord no later than June 1, 2012 (the “ Phase 1 Premises Deadline ”). If Tenant fails to
provide Landlord with such notice by the Phase 1 Premises Deadline, then the Phase 1 Premises shall be as shown on Exhibit B-
2 attached hereto. Promptly following the Phase 1 Premises Deadline, the parties shall enter into a written instrument confirming
the square footage of Rentable Area of the Phase 1 Premises. The “ Phase 2 Premises ” shall consist of the balance of the
Premises. The Rent Commencement Date shall be determined separately for each Phase and Base Rent shall be prorated based
on the ratio of square footage of the Phase 1 Premises to the entire Premises until such time as the “Rent Commencement Date” 
occurs with respect to the entire Premises (i.e., until such time as the Phase 2 Premises Rent Commencement Date occurs). The “ 
Phase 1 Premises Rent Commencement Date ” shall be the earlier of (a) the Date earlier to occur of (i) Substantial Completion of 
the work described on Exhibit B with respect to the Phase 1 Premises (the “ Phase 1 Premises Tenant Improvements ”), and
(ii) January 1, 2013 and (b) the date on which Tenant has occupied any portion of the Phase 1 Premises for the conduct of its 
business, as opposed to occupying any portion of the Phase 1 Premises for the installation of the Tenant Improvements (as
defined below). The “ Phase 2 Premises Rent Commencement Date ” shall be the earlier of (y) the Date that is the earlier to occur 
of (i) Substantial Completion of the work described on Exhibit B with respect to the Phase 2 Premises (the “ Phase 2 Premises
Tenant Improvements ” and, together with the Phase 1 Premises Tenant Improvements, the
  
                                                                5


“ Tenant Improvements ”), and (ii) November 1, 2013 and (z) the date on which Tenant has occupied any portion of the Phase 2 
Premises for the conduct of its business, as opposed to occupying any portion of the Phase 2 Premises for the installation of
the Tenant Improvements. Each of the Phase 1 Premises Rent Commencement Date and the Phase 2 Premises Rent
Commencement Date shall be subject to extension for Landlord Delay as further described in Section 4 of Exhibit B hereto. Each
party shall execute and deliver to the other written acknowledgment of the actual Commencement Date, the actual Phase 1
Premises Rent Commencement Date, the actual Phase 2 Premises Rent Commencement Date and/or the Term Expiration Date
within ten (10) business days after request by the other party, substantially in the form attached as Exhibit C hereto. Failure to
execute and deliver such acknowledgment, however, shall not affect the Phase 1 Premises Rent Commencement Date, the Phase
2 Premises Rent Commencement Date, the Term Expiration Date or Landlord’s or Tenant’s liability hereunder. The term “ 
Substantially Complete ” or “ Substantial Completion ” means that the applicable Phase of Tenant Improvements is
substantially complete in accordance with the Approved Plans (as defined in Exhibit B hereto), except for minor punch list items,
and that Tenant is able to lawfully occupy the Premises for the conduct of its business in accordance with the Permitted Use.
      4.2. Tenant shall cause the Tenant Improvements to be constructed in the Premises pursuant to the Work Letter attached
hereto as Exhibit B (the “ Work Letter ”) at a cost to Landlord not to exceed Eighteen Million Nine Hundred Nine Thousand
Seven Hundred Fifty and 00/100 Dollars ($18,909,750.00) (based upon One Hundred Fifty and 00/100 Dollars ($150.00) per
square foot of Rentable Area (as defined below)) (the “ TI Allowance ”). The TI Allowance may be applied to the costs of
(s) construction, (t) building permits and other permits, approvals, taxes, fees, charges and levies by Governmental Authorities 
(as defined below) for permits or for inspections of the Tenant Improvements, and (u) costs and expenses for labor, material, 
equipment and fixtures. In no event shall the TI Allowance be used for (v) the cost of work that is not authorized by the 
Approved Plans (as defined in the Work Letter) or otherwise approved in writing by Landlord, (w) payments to Tenant or any 
affiliates of Tenant, (x) Tenant’s soft costs or the purchase of any furniture, personal property or other non-building system
equipment, (y) costs resulting from any default by Tenant of its obligations under this Lease or (z) costs to extent recoverable 
by Tenant from a third party (e.g., insurers, warrantors, or tortfeasors). Notwithstanding the foregoing to the contrary, Tenant
may apply up to ten percent (10%) of the TI Allowance toward the costs of Tenant’s architectural, engineering, and project
management fees, data/telecom cabling, relocation expenses, and an additional amount up to ten percent (10%) of the TI 
Allowance towards the costs of Tenant’s furniture, fixtures and equipment installation related to the initial occupancy of the
Premises. In no event shall any unused TI Allowance entitle Tenant to a credit against Rent payable under this Lease. Tenant
shall have until May 31, 2014 (the “ TI Deadline ”) to requisition the unused portion of the TI Allowance, after which date
Landlord’s obligation to fund such costs shall expire.

     4.3. The Phase 1 Premises and Phase 2 Premises are sometimes generically referred to herein as a “Phase”.
  
                                                                 6


    4.4. Prior to entering upon the Premises, Tenant shall furnish to Landlord evidence satisfactory to Landlord that insurance
coverages required of Tenant under the provisions of Article 23 are in effect.

5. Condition of Premises . Tenant acknowledges that neither Landlord nor any agent of Landlord has made any
representation or warranty with respect to the condition of the Premises, the Building or the Property, or with respect to
the suitability of the Premises, the Building or the Property for the conduct of Tenant’s business, except as expressly set
forth in this Lease. Without in any way derogating from Landlord’s ongoing maintenance, repair and restoration
obligations set forth elsewhere in this Lease, Tenant acknowledges that (a) it is familiar with the condition of the Premises 
and agrees to take the same in its condition “as is” as of the Execution Date and (b) Landlord shall have no obligation to 
alter, repair or otherwise prepare the Premises for Tenant’s occupancy or to pay for or construct any improvements to the
Premises, except with respect to the TI Allowance; provided, however, that Landlord shall separately demise that portion
of the Premises located on the fourth (4th) floor of the Building separately as shown on Exhibit B-1 attached hereto and
furnish and provide a reception desk in the main building lobby as further provided in Exhibit B , at Landlord’s sole cost
and expense (in addition to the TI Allowance).

6. Rentable Area . The Rentable Areas initially set forth herein are deemed conclusive between the parties and are not subject to
remeasurement, except that in the event that the size of the Premises or Building is actually reduced or expanded pursuant to the
provisions of Articles 1, 24, 25, 43 or 44 below, the Rentable Areas (and, as applicable, Tenant’s Pro Rata Share) shall be
adjusted as reasonably calculated by Landlord’s architect in a manner consistent with Landlord’s initial determination of
Rentable Areas for the Premises and the Building.
Rentable Areas for the Premises and the Building.

7. Rent .
     7.1. Tenant shall pay to Landlord as Base Rent for the Premises, commencing on the Phase 1 Premises Rent
Commencement Date, the sums set forth in Section 2.3 , subject to the rental adjustments provided in Section 4.1 and Article 8
hereof. Base Rent shall be paid in equal monthly installments, subject to the rental adjustments provided in Section 4.1 and
Article 8 hereof, each in advance on the first day of each and every calendar month during the Term.

      7.2. In addition to Base Rent, Tenant shall pay to Landlord as additional rent (“ Additional Rent ”) at times hereinafter
specified in this Lease (a) Tenant’s Share (as defined below) of Operating Expenses (as defined below), (b) the Property 
Management Fee (as defined below) and (c) any other amounts that Tenant assumes or agrees to pay under the provisions of 
this Lease that are owed to Landlord, including any and all other sums that may become due by reason of any default of Tenant
or failure on Tenant’s part to comply with the agreements, terms, covenants and conditions of this Lease to be performed by
Tenant, after notice and the lapse of any applicable cure periods.

     7.3. Base Rent and Additional Rent shall together be denominated “Rent.” Rent shall be paid to Landlord in lawful money
of the United States of America at the office of Landlord as set forth in Section 2.8 or to such other person or at such other 
place as Landlord may from time designate in writing. In the event the Phase 1 Rent Commencement Date or Phase 2 Rent
  
                                                                 7


Commencement Date occurs or the Term ends on a day other than the first day of a calendar month, then the Rent for such
fraction of a month shall be prorated for such period on the basis of a thirty (30) day month and shall be paid at the then-current
rate for such fractional month. All payments of Rent shall be made without set-off, deduction or offset except as expressly
provided in this Lease. Without limiting the foregoing, Tenant’s obligation to pay Rent shall be absolute, unconditional, and
independent and shall not be discharged or otherwise affected by any Applicable Laws now or hereafter applicable to the
Premises, or any other restriction on Tenant’s use, or, except as provided in Articles 24 and 25 , any casualty or taking, or any
failure by Landlord to perform or other occurrence; and Tenant assumes the risk of the foregoing and waives all rights now or
hereafter existing to quit or surrender the Premises or any part thereof, to terminate or cancel this Lease, or to assert any defense
in the nature of constructive eviction in any action seeking to recover rent (other than mandatory counterclaims). Subject to the
provisions of this Lease, however, Tenant shall have the right to injunctive relieve or to seek judgments for direct money
damages occasioned by Landlord’s breach of its Lease covenants (but may not set-off any such judgment against any rent or
other amount owing hereunder). Nothing in this Section 7.3 shall limit the exercise of Tenant’s express remedies on the terms
and conditions set forth in Sections 16.2 and  18.3 below).

8. Rent Adjustments . Base Rent shall be subject to an annual upward adjustment of three percent (3%) of the then-current Base
Rent during the initial Term. The first such adjustment shall become effective commencing on the first (1 st ) annual anniversary 
of the Phase 1 Premises Rent Commencement Date, and subsequent adjustments shall become effective on every successive
annual anniversary for the remainder of the initial Term of this Lease.
9. Operating Expenses .
     9.1. As used herein, the term “ Operating Expenses ” shall include:

           (a) Government impositions, including property tax costs consisting of real and personal property taxes and
assessments (including amounts due under any improvement bond upon the Building or the Property (including the parcel or
parcels of real property upon which the Building, the other buildings on the Property and areas serving the Building and the
Property are located)) or assessments in lieu thereof imposed by any federal, state, regional, local or municipal governmental
authority, agency or subdivision (each, a “ Governmental Authority ”); taxes on or measured by gross rentals received from the
rental of space in the Property; taxes based on the square footage of the Premises, the Building or the Property, as well as any
parking charges, utilities surcharges or any other costs levied, assessed or imposed by, or at the direction of, or resulting from
Applicable Laws or interpretations thereof, promulgated by any Governmental Authority in connection with the use or
occupancy of the Building or Property or the parking facilities serving the Building; any actual and reasonable third party
expenses, including the reasonable cost of attorneys or experts, reasonably incurred by Landlord in seeking reduction by the
taxing authority of the applicable taxes. If Landlord is successful in obtaining any refund, abatement or other reduction of any
taxes payable in respect of the Property for any year for which Tenant has paid Operating Expenses, Landlord shall promptly
refund to Tenant Tenant’s Pro Rata Share of the Building of such refund, abatement or other reduction (including any interest
paid by the taxing authority),
  
                                                                  8


but in any event not to exceed amounts actually paid by Tenant on account of such taxes during such period. To the extent that
Landlord is billed for any taxes on the execution of this Lease or any other document to which Tenant is a party creating or
transferring an interest in the Premises, Tenant shall pay the same directly to Landlord within thirty (30) days after receipt of an 
invoice therefor (which invoice shall be accompanied by a copy of the applicable tax bill(s)). Operating Expenses shall not
include any state, federal or local net income, franchise, capital stock, estate, transfer or inheritance taxes, or taxes that are the
personal obligation of Tenant or of another tenant of the Property; and

          (b) All other actual third party costs (or costs for Landlord personnel or services provided by Landlord so long as the
same is provided at a cost that does not exceed the cost of such personnel or service rendered by unaffiliated third parties on a
competitive basis) of any kind paid or incurred by Landlord in connection with the operation or maintenance of the Building and
the Property, including costs of repairs and replacements to improvements within the Property as appropriate to maintain the
Property as required hereunder; costs of utilities furnished to the Common Areas; sewer fees; trash collection (including
recyclables, but excluding special handling or collection costs associated with collection of any Hazardous Materials not
customarily collected in the ordinary maintenance of a first class office and laboratory building); Common Area cleaning,
including windows; heating; ventilation; air-conditioning; maintenance of landscaping and grounds; maintenance of drives and
parking areas; maintenance of the roof; security services and devices; building supplies; maintenance or replacement of
equipment utilized for operation and maintenance of the Property; license, permit and inspection fees; sales, use and excise
taxes on goods and services purchased by Landlord in connection with the operation, maintenance or repair of the Building or
taxes on goods and services purchased by Landlord in connection with the operation, maintenance or repair of the Building or
Property systems and equipment; telephone, postage, stationery supplies and other expenses incurred in connection with the
operation, maintenance or repair of the Property; accounting, legal and other professional fees and expenses incurred in
connection with the Property; costs of furniture, draperies, carpeting, landscaping, snow removal and other customary and
ordinary items of personal property provided by Landlord for use in Common Areas; Property office rent or rental value for a
commercially reasonable amount of space, to the extent an office used for Property operations is maintained at the Property,
plus customary expenses for such office; capital expenditures amortized over the useful life thereof, as reasonably determined
by Landlord, in accordance with generally accepted accounting principles ; costs of complying with Applicable Laws (except to
the extent such costs are incurred to remedy non-compliance as of the Execution Date with Applicable Laws); costs to keep the
Property in compliance with, or fees otherwise required under, any Property Operations Agreements (as defined below);
insurance premiums; portions of insured losses paid by Landlord as part of a deductible portion of a loss pursuant to the terms
of insurance policies (provided that such deductibles are commercially reasonable); service contracts; costs of services of
independent contractors retained to do work of a nature referenced above; and costs of compensation (including employment
taxes and fringe benefits) of all persons who perform regular and recurring duties connected with the day-to-day operation and
maintenance of the Property, its equipment, the adjacent walks, landscaped areas, drives and parking areas, including janitors,
floor waxers, window washers, watchmen, gardeners, sweepers, plow trucks and handymen. Operating Expenses for each year
will be calculated in a reasonably consistent manner.
  
                                                                  9


            (c) Notwithstanding the foregoing, Operating Expenses shall not include any (i) leasing commissions; (ii) expenses 
that relate to preparation of rental space for a tenant; (iii) expenses of initial development and construction of the Building, or of 
any expansion or elective upgrade (other than for the primary purpose of reducing Operating Expenses as described in clause
(x) below) of the Building or Common Areas, including grading, paving, landscaping and decorating (as distinguished from 
maintenance, repair and replacement of the foregoing); (iv) legal expenses relating to other tenants; (v) costs of repairs to the 
extent Landlord is entitled to be reimbursed by payment of insurance, warranties or guaranties or by any other third party or
parties; (vi) principal amount of, or interest upon loans to Landlord or secured by a mortgage or deed of trust covering the 
Property or a portion thereof; (vii) costs to operate, maintain, or repair the Garage; (viii) salaries of executive officers of 
Landlord; (ix) depreciation claimed by Landlord for tax purposes (other than amortization of capital expenditures as expressly 
provided herein); (x) capital improvements (as distinguished from repairs and maintenance) unless and except to the extent 
incurred (i) in replacing obsolete equipment or other capital items, (ii) for the primary purpose of reducing Operating Expenses or 
(iii) required by any Governmental Authority to comply with changes in Applicable Laws that take effect after the Execution 
Date or to ensure continued compliance with Applicable Laws in effect as of the Execution Date (but expressly excluding the
costs of curing or contesting violations of Applicable Law that existed on or prior to the Execution Date); (xi) the cost of 
leasehold improvements, including without limitation redecorating or renovation work, for other tenants in the Building; (xii) to 
the extent of any increase in Landlord’s insurance rates which may result from the grossly negligent failure of Landlord or its
agents, employees or contractors to comply with the provisions of this Lease; (xiii) the cost of any work or service performed 
for any tenant in the Building (other than Tenant) to a materially greater extent or in a materially more favorable manner than that
furnished generally to tenants (including Tenant) in the Building; (xiv) the general corporate overhead costs and expenses of 
the Landlord entity (except to the extent of the Property Management Fee and personnel costs at the level of Senior Property or
Facilities Manager and below to the extent related to the Property); (xv) costs and expenses incurred in any dispute with any 
particular tenant; (xvi) any costs of remediation of hazardous materials or substances in the Building, or on the land parcels on 
which it is located; (xvii) any costs (other than the Property Management Fee described below) representing an amount paid to 
an entity related to Landlord which is in excess of the amount which would have been paid absent such relationship; and
(xviii) taxes that are excluded from Operating Expenses by the last sentence of Subsection 9.1(a) . To the extent that Tenant uses
more than Tenant’s Pro Rata Share of the Building of any item of Operating Expenses, Landlord shall provide notice to Tenant
of such excess usage, and Tenant shall pay Landlord for such excess in addition to Tenant’s obligation to pay Tenant’s Pro
Rata Share of Lab Building of Operating Expenses for the Property (such excess, together with Tenant’s Pro Rata Share of Lab
Building, “ Tenant’s Share ”). Notwithstanding anything in this Article 9 to the contrary, Tenant’s Share with respect to taxes
and other impositions as set forth in Subsection 9.1(a) and to expenses payable by the Building under the CC&Rs shall mean
such excess together with Tenant’s Pro Rata Share of the Building. Nothing in this paragraph shall be deemed to limit the extent
to which CC&Rs are included in Operating Expenses.

    9.2. Tenant shall pay to Landlord on the first day of each calendar month of the Term, following the Phase 1 Premises Rent
Commencement Date, as Additional Rent, (a) the Property Management Fee (as defined below) and (b) Landlord’s estimate of
Tenant’s Share of Operating Expenses for such month.
  
                                                                10


          (x) The “ Property Management Fee ” shall equal three percent (3%) of Base Rent due from Tenant. Tenant shall pay 
the Property Management Fee in accordance with Section 9.2 with respect to the entire Term, commencing on the applicable
Rent Commencement Date, including any extensions thereof or any holdover periods, regardless of whether Tenant is obligated
to pay Base Rent, Operating Expenses or any other Rent with respect to any such period or portion thereof, except as expressly
provided in this Lease.

           (y) Within ninety (90) days after the conclusion of each calendar year (or such longer period as may be reasonably 
required by Landlord but in any event not to exceed one year), Landlord shall furnish to Tenant a statement showing in
reasonable detail the actual Operating Expenses and Tenant’s Share of Operating Expenses for the previous calendar year. Any
additional sum due from Tenant to Landlord shall be due and payable within thirty (30) days. If the amounts paid by Tenant 
pursuant to this Section exceed Tenant’s Share of Operating Expenses for the previous calendar year, then Landlord shall credit
the difference against Tenant’s Share of Operating Expenses next due and owing from Tenant; provided that, if the Term has
expired, Landlord shall accompany such statement with payment for the amount of such difference.

          (z) Any amount due under this Section for any period that is less than a full month shall be prorated (based on a thirty
(30)-day month) for such fractional month.

     9.3. Landlord’s annual statement shall be final and binding upon Tenant unless Tenant, within 180 days after Tenant’s
receipt thereof, shall contest any item therein by giving written notice to Landlord, specifying in reasonable detail the reasons
therefor; provided that Tenant shall in all events pay the amount specified in Landlord’s annual statement, pending the results
therefor; provided that Tenant shall in all events pay the amount specified in Landlord’s annual statement, pending the results
of the Independent Review and determination of the Accountant(s), as applicable and as each such term is defined below. At
the request of Tenant at any time within such 180-day period, Landlord shall provide Tenant with reasonable access to
Landlord’s books and records to the extent relevant to determination of Operating Expenses, and such information as Landlord
reasonably determines to be responsive to Tenant’s written inquiries. In the event that, after Tenant’s review of such
information, Landlord and Tenant cannot agree upon the amount of Tenant’s Share of Operating Expenses, then Tenant shall
have the right to have a qualified and reputable third party consultant or accounting firm hired by Tenant (but not on a
contingent-fee basis) at Tenant’s sole cost and expense audit and review such of Landlord’s books and records for the year in
question as directly relate to the determination of Operating Expenses for such year (the “ Independent Review ”). Landlord
shall make such books and records available at the location where Landlord maintains them in the ordinary course of its
business, but need not provide Tenant with copies of any books or records. Tenant shall commence the Independent Review
within thirty (30) days after the date Landlord has given Tenant access to Landlord’s books and records for the Independent
Review and following at least 10 days’ prior notice to Landlord of the identity of the consultant or accounting firm conducting
such review so that Landlord can confirm that such reviewer meets the foregoing qualifications. Tenant shall complete the
Independent Review and notify Landlord in writing of
  
                                                               11


Tenant’s specific objections to Landlord’s calculation of Operating Expenses (including Tenant’s accounting firm’s written
statement of the basis, nature and amount of each proposed adjustment) no later than sixty (60) days after Landlord has first 
given Tenant access to Landlord’s books and records for the Independent Review. Landlord shall review the results of any
such Independent Review. The parties shall endeavor to agree promptly and reasonably upon Operating Expenses taking into
account the results of such Independent Review. If, as of sixty (60) days after Tenant has submitted the Independent Review to 
Landlord, the parties have not agreed on the appropriate adjustments to Operating Expenses, then the parties shall engage a
mutually agreeable independent third party accountant with at least ten (10) years’ experience in commercial real estate
accounting in the Kendall Square, Cambridge, Massachusetts area (the “ Accountant ”). If the parties cannot agree on the
Accountant, each shall within ten (10) days after such impasse appoint an Accountant (different from the accountant and 
accounting firm that conducted the Independent Review) and, within ten (10) days after the appointment of both such 
Accountants, those two Accountants shall select a third (which cannot be the accountant and accounting firm that conducted
the Independent Review). If either party fails to timely appoint an Accountant, then the Accountant the other party appoints
shall be the sole Accountant. Within ten (10) days after appointment of the Accountant(s), Landlord and Tenant shall each 
simultaneously give the Accountants (with a copy to the other party) its determination of Operating Expenses, with such
supporting data or information as each submitting party determines appropriate. Within ten (10) days after such submissions, 
the Accountants shall by majority vote select either Landlord’s or Tenant’s determination of Operating Expenses. The
Accountants may not select or designate any other determination of Operating Expenses. The determination of the Accountant
(s) shall bind the parties. If the parties agree or the Accountant(s) determine that the Operating Expenses actually paid by
Tenant for the calendar year in question exceeded Tenant’s obligations for such calendar year, then Landlord shall, at Tenant’s
option, either (a) credit the excess to the next succeeding installments of estimated Additional Rent or (b) pay the excess to 
Tenant within thirty (30) days after delivery of such results. If the parties agree or the Accountant(s) determine that Tenant’s
payments of Operating Expenses for such calendar year were less than Tenant’s obligation for the calendar year, then Tenant
shall pay the deficiency to Landlord within thirty (30) days after delivery of such results. If the Independent Review reveals or 
the Accountant(s) determine that the Operating Expenses billed to Tenant by Landlord and paid by Tenant to Landlord for the
applicable calendar year in question exceeded by more than four percent (4%) what Tenant should have been billed during such 
calendar year, then Landlord shall pay the reasonable cost of the Independent Review and the Accountants. In all other cases,
Tenant shall pay the cost of the Independent Review, and one-half of the cost of the Accountants. Any Operating Expense not
billed to Tenant on or before the second (2 nd ) anniversary of the last day of the calendar year in which such Operating Expense 
was billed to or incurred by Landlord shall be deemed waived by Landlord, and Tenant shall have no liability or obligation with
was billed to or incurred by Landlord shall be deemed waived by Landlord, and Tenant shall have no liability or obligation with
respect thereto.

     9.4. Tenant shall not be responsible for Operating Expenses attributable to the time period prior to the Phase 1 Premises
Rent Commencement Date, with respect to the Phase 1 Premises; or the Phase 2 Premises Rent Commencement Date, with
respect to the Phase 2 Premises.
     9.5. Operating Expenses for the calendar year in which Tenant’s obligation to share therein commences and for the
calendar year in which such obligation ceases shall be prorated
  
                                                                 12


on a commercially reasonable basis determined by Landlord and consistent with generally accepted commercial property
accounting principles. Expenses such as taxes, assessments and insurance premiums that are incurred for an extended time
period shall be prorated based upon the time periods to which they apply so that the amounts attributed to the Premises relate
in a reasonable manner to the time period wherein Tenant has an obligation to share in Operating Expenses.

     9.6. In the event that the Building is less than fully occupied, Tenant acknowledges that Landlord may extrapolate those
particular items of Operating Expenses that vary depending on the occupancy of the Building to reflect the amount that would
have been incurred for those particular expenses had the entire Building been occupied during such period; provided , however,
that Landlord shall not recover more than one hundred percent (100%) of Operating Expenses. 

10. Taxes on Tenant’s Property .
      10.1. Tenant shall be responsible for any and all taxes levied against any personal property or trade fixtures placed by
Tenant in or about the Premises. Tenant shall not be deemed to be in default of its obligations under the preceding sentence in
the event that Tenant shall contest the validity of any such taxes by appellate or other proceedings permitted under Applicable
Laws, provided that: (a) any such contest is made reasonably and in good faith, (b) Tenant makes commercially reasonable 
provisions reasonably acceptable to Landlord (which shall include posting bond(s) or giving other security satisfactory to
Landlord if the Building or the Property are subjected to any liens arising out of such failure to pay or contest, with Tenant in
each case agreeing to discharge or bond over any such liens within 15 days after such liens arise) to protect Landlord, the
Building and the Property from any liabilities, costs, damages and expenses arising in connection with Tenant’s inability to pay,
or the contest of, such taxes, (c) Tenant agrees to indemnify, defend (with counsel reasonably acceptable to Landlord) and hold 
Landlord harmless from and against any and all liabilities, costs, damages and expenses arising in connection with Tenant’s
failure to pay, or contest of, such taxes as required by Applicable Law, and (d) Tenant promptly pays any and all such taxes in 
the event that it exhausts all available appeals without success or if such payment is required as a precondition to such contest.

      10.2. If (a) (i) any such taxes on Tenant’s personal property or trade fixtures are levied against Landlord or Landlord’s
property, or (ii) the assessed valuation of the Building or the Property is increased by inclusion therein of a value specifically 
attributed to Tenant’s personal property or trade fixtures, as evidenced by information provided in writing by the tax assessor,
and (b) Landlord, after written notice to Tenant, pays the taxes on Tenant’s personal property or trade fixtures, then Tenant
shall, upon demand, repay to Landlord the taxes so paid by Landlord.
  
                                                                 13


11. Security Deposit .
     11.1. Tenant shall deposit with Landlord on or before the Execution Date a letter of credit (the “ L/C Security ”) as the entire
security deposit (the “ Security Deposit ”), as follows:

           (a) Tenant shall provide Landlord, and maintain in full force and effect throughout the Term and until the date that is
ninety (90) days after the then-current Term Expiration Date, a letter of credit substantially in the form of Exhibit E issued by an
issuer reasonably satisfactory to Landlord, in the amount of the Security Deposit, with an initial term of at least one year.
Landlord may require the L/C Security to be replaced by an L/C Security issued by a different issuer at any time during the Term
if Landlord reasonably believes that the issuing bank of the L/C Security is or may soon become insolvent, in which event
Landlord shall cooperate with Tenant to arrange for the replacement of the L/C Security in a manner that does not require the
simultaneous issuance of two (2) letters of credit. If Tenant has actual notice, or Landlord notifies Tenant at any time, that any 
issuer of the L/C Security has become insolvent or placed into FDIC receivership, then Tenant shall promptly deliver to
Landlord (without the requirement of further notice from Landlord) substitute L/C Security issued by an issuer reasonably
satisfactory to Landlord, and otherwise conforming to the requirements set forth in this Article. As used herein with respect to
the issuer of the L/C Security, “insolvent” shall mean the determination of insolvency as made by such issuer’s primary bank
regulator (i.e., the state bank supervisor for state chartered banks; the OCC or OTS, respectively, for federally chartered banks
or thrifts; or the Federal Reserve for its member banks).

            (b) Landlord may draw upon the L/C Security, and hold and apply the proceeds for the payment of any Rent or any
other sum in default, or to compensate Landlord for any other loss or damage that Landlord may suffer by reason of Tenant’s
default, if: (i) a Default (as defined below) exists (or would have existed with the giving of notice and passage of applicable cure 
periods, but only if transmittal of a default notice is stayed or barred by applicable bankruptcy or other similar law), provided
that such draw pursuant to his clause (i) shall be limited to the amount that Landlord reasonably determines is required to cure 
such Default; (ii) as of the date forty-five (45) days before any L/C Security expires Tenant has not delivered to Landlord an 
amendment or replacement for such L/C Security, reasonably satisfactory to Landlord, extending the expiry date to the earlier of
(1) ninety (90) days after the then-current Term Expiration Date or (2) the date one year after the then-current expiry date of the
L/C Security; (iii) Tenant fails to pay (when and as Landlord reasonably requires) any bank charges for Landlord’s transfer of
the L/C Security; or (iv) the issuer of the L/C Security ceases, or announces that it will cease, to maintain an office in the city 
where Landlord may present drafts under the L/C Security (and fails to permit drawing upon the L/C Security by overnight
courier or facsimile). This Section does not limit any other provisions of this Lease allowing Landlord to draw the L/C Security
under specified circumstances. In the event of any such draw upon the L/C Security, Tenant shall within 10 days thereafter
provide Landlord with a replacement letter of credit, or amendment to the existing letter of credit increasing the amount of such
letter of credit, in the amount of L/C Security required hereunder, and Tenant’s failure to do so shall be a material breach of this
Lease. Landlord shall hold the proceeds of any draw not applied as set forth above as a cash Security Deposit as further
described below.

            (c) If Landlord transfers its interest in the Premises, then Landlord shall transfer the L/C Security to the transferee of
its interest, and Tenant shall at Tenant’s expense, within fifteen (15) business days after receiving a request from Landlord, 
deliver (and, if the issuer requires, Landlord shall consent to) an amendment to the L/C Security naming Landlord’s grantee as
substitute beneficiary. If the required Security Deposit changes while L/C Security is in force, then Tenant shall deliver (and, if
the issuer requires, Landlord shall consent to) a corresponding amendment to the L/C Security.
  
                                                                  14


           (d) If and to the extent Landlord is holding the proceeds of the L/C Security in cash from time to time, such cash shall
be held by Landlord as security for the faithful performance by Tenant of all of the terms, covenants and conditions of this
Lease to be kept and performed by Tenant during the period commencing on the Execution Date and ending upon the expiration
or termination of Tenant’s obligations under this Lease. If Tenant Defaults with respect to any provision of this Lease,
including any provision relating to the payment of Rent, then Landlord may (but shall not be required to) use, apply or retain all
or any part of the Security Deposit for the payment of any Rent or any other sum in Default, or to compensate Landlord for any
other loss or damage that Landlord may suffer by reason of Tenant’s Default as provided in this Lease. The provisions of this
Article shall survive the expiration or earlier termination of this Lease. In the event of bankruptcy or other debtor-creditor
proceedings against Tenant, any cash Security Deposit then being held by Landlord shall be deemed to be applied first to the
payment of Rent and other charges due Landlord for all periods prior to the filing of such proceedings. Landlord shall deliver or
credit to any purchaser of Landlord’s interest in the Premises the funds then held hereunder by Landlord, and thereupon (and
upon confirmation by the transferee of such funds, whether expressly or by written assumption of this Lease, generally)
Landlord shall be discharged from any further liability with respect to such funds. This provision shall also apply to any
subsequent transfers. If Tenant shall fully and faithfully perform every provision of this Lease to be performed by it, then the
Security Deposit, if any, or any balance thereof, shall be returned to Tenant (or, at Landlord’s option, to the last assignee of
Tenant’s interest hereunder) within 90 days after the expiration or earlier termination of this Lease. If and to the extent the
Security Deposit shall be in cash, Landlord shall hold the Security Deposit in an account at a banking organization selected by
Landlord; provided , however, that Landlord shall not be required to maintain a separate account for the Security Deposit, but
may intermingle it with other funds of Landlord. Landlord shall be entitled to all interest and/or dividends, if any, accruing on
the Security Deposit. Landlord shall not be required to credit Tenant with any interest for any period during which Landlord
does not receive interest on the Security Deposit.

12. Use .
     12.1. Tenant shall use the Premises for the purpose set forth in Section 2.7 , and shall not use the Premises, or permit or
     12.1. Tenant shall use the Premises for the purpose set forth in Section 2.7 , and shall not use the Premises, or permit or
suffer the Premises to be used, for any other purpose without Landlord’s prior written consent, which consent Landlord may
withhold in its sole and absolute discretion.

     12.2. Tenant shall not use or occupy the Premises in violation of Applicable Laws; zoning ordinances; or the certificate of
occupancy issued for the Building or the Property, and shall, upon five (5) days’ written notice from Landlord, discontinue any
use of the Premises that is declared or claimed by any Governmental Authority having jurisdiction to be a violation of any of the
above, or that in Landlord’s reasonable opinion violates any of the above. Tenant shall comply with any direction of any
Governmental Authority having jurisdiction that shall, solely by reason of the nature of Tenant’s use or occupancy of the
Premises (other than for general office or laboratory use), impose any duty upon Tenant or Landlord with respect to the
Premises or with respect to the use or occupation thereof.
  
                                                                 15


      12.3. Tenant shall not do or permit to be done anything that will invalidate or increase the cost of any fire, environmental,
extended coverage or any other insurance policy covering the Building or the Property, and shall comply with all commercially
reasonable and customary rules, orders, regulations and requirements of the insurers of the Building and the Property, and
Tenant shall promptly, upon demand, reimburse Landlord for any additional premium charged for such policy solely by reason
of Tenant’s failure to comply with the provisions of this Article, or cease the applicable activity, to the extent that ceasing such
activity does in fact prevent such cost increase from occurring. The use of the Premises for office or laboratory uses, generally,
will not result in a breach of the provisions of this paragraph.

     12.4. Tenant shall keep all doors opening onto public corridors closed, except when in use for ingress and egress.

     12.5. No additional locks or bolts of any kind shall be placed upon any of the doors or windows by Tenant, nor shall any
changes be made to existing locks or the mechanisms thereof without Landlord’s prior written consent. Tenant shall, upon
termination of this Lease, return to Landlord all keys to offices and restrooms either furnished to or otherwise procured by
Tenant. In the event any key so furnished to Tenant is lost, Tenant shall pay to Landlord the cost of replacing the same or of
changing the lock or locks opened by such lost key if Landlord shall deem it necessary to make such change.

     12.6. No awnings or other projections shall be attached to any outside wall of the Building. No curtains, blinds, shades or
screens shall be attached to or hung in, or used in connection with, any exterior or atrium window or door of the Premises other
than Landlord’s standard window coverings as described in the Tenant Manual. Neither the interior nor exterior of any
windows shall be coated or otherwise sunscreened without Landlord’s prior written consent, nor shall any bottles, parcels or
other articles be placed on the windowsills. No equipment, furniture or other items of personal property shall be placed on any
exterior balcony without Landlord’s prior written consent.

     12.7. No sign, advertisement or notice (“ Signage ”) shall be exhibited, painted or affixed by Tenant on any part of the
Premises or the Building without Landlord’s prior written consent, which may be withheld in Landlord’s sole discretion, except
as expressly set forth in this Section 12.7. Tenant shall be entitled to install and maintain, at its sole cost and expense, (1) one 
exterior sign identifying Tenant on the facade of the Building to be located within the area designated on Exhibit L attached
hereto, and (2) interior entry signage on doors to the Premises in Landlord’s reasonable discretion (to the extent visible from
Common Areas) and in a manner consistent with Landlord’s reasonable Building Standards, subject in each case to all
Applicable Laws, codes and ordinances and Landlord’s reasonable approval with regards to installation, size, design, location
and other reasonable criteria (provided, however, the standard corporate lettering and logo of Tenant are hereby approved). For
any Signage, Tenant shall, at Tenant’s own cost and expense, (a) acquire all permits for such Signage in compliance with 
Applicable Laws and (b) design, fabricate, install and maintain such Signage in a first-class condition. Tenant shall be
responsible for removing any of Tenant’s Signage upon the expiration
  
                                                                 16


or earlier termination of this Lease. The directory tablet shall be inscribed, painted or affixed for Tenant by Landlord at
or earlier termination of this Lease. The directory tablet shall be inscribed, painted or affixed for Tenant by Landlord at
Landlord’s sole cost and expense, and shall be of a size, color and type and be located in a place acceptable to Landlord. The
directory tablet shall be provided exclusively for the display of the name and location of tenants only. Tenant shall not place
anything on the exterior of the corridor walls or corridor doors other than Landlord’s standard lettering.

     12.8. Tenant shall only place equipment within the Premises with floor loading consistent with the Building’s structural
design (which is 100 psf) without Landlord’s prior written approval, and such equipment shall be placed in a location designed
to carry the weight of such equipment.

     12.9. Tenant shall cause any equipment or machinery to be installed in the Premises so as to reasonably prevent sounds or
vibrations therefrom from extending into the Common Areas or other offices in the Property.

     12.10. Tenant shall not (a) do or permit anything to be done in or about the Premises that shall in any way unreasonably 
obstruct or interfere with the rights of other tenants or occupants of the Property, or injure them, (b) use or allow the Premises 
to be used for unlawful purposes, (c) cause, maintain or permit any nuisance or waste in, on or about the Property or (d) take 
any other action that would in Landlord’s reasonable determination in any manner unreasonably and adversely affect other
tenants’ quiet use and enjoyment of their space or adversely impact their ability to conduct business in a professional and
suitable work environment for office and laboratory uses.

      12.11. Landlord shall be responsible for ensuring the Common Areas comply with the Americans with Disabilities Act, 42
U.S.C. § 12101, et seq., and any state and local accessibility laws, codes, ordinances and rules (collectively, and together with 
regulations promulgated pursuant thereto, the “ ADA ”) to (which cost may be included in Operating Expenses) and that the
Landlord Demising Work is performed in compliance with the ADA. Subject to the foregoing, Tenant shall be responsible for all
liabilities, costs and expenses arising out of or in connection with the compliance of the Premises with the ADA, and Tenant
shall indemnify, save, defend (at Landlord’s option and with counsel reasonably acceptable to Landlord) and hold Landlord and
its affiliates, employees, agents and contractors; and any lender, mortgagee or beneficiary (each, a “ Lender ” and, collectively
with Landlord and its affiliates, employees, agents and contractors, the “ Landlord Indemnitees ”) harmless from and against
any demands, claims, liabilities, losses, costs, expenses, actions, causes of action, damages or judgments, and all reasonable
expenses (including reasonable attorneys’ fees, charges and disbursements) incurred in investigating or resisting the same
(collectively, “ Claims ”) arising out of any such failure of the Premises to comply with the ADA. This Section (as well as any
other provisions of this Lease dealing with indemnification of the Landlord Indemnitees by Tenant shall be deemed to be
modified in each case by the insertion in the appropriate place of the following: “except as otherwise provided in Mass. G.L. Ter.
Ed., C. 186, Section 15.” The provisions of this Section shall survive the expiration or earlier termination of this Lease.
  
                                                                 17


      12.12. Tenant shall establish and maintain a chemical safety program administered by a licensed, qualified individual in
accordance with the requirements of the Massachusetts Water Resources Authority (“ MWRA ”) and any other applicable
Governmental Authority. Tenant shall be solely responsible for all costs incurred in connection with such chemical safety
program, and Tenant shall provide Landlord with such documentation as Landlord may reasonably require evidencing Tenant’s
compliance with the requirements of (a) the MWRA and any other applicable Governmental Authority with respect to such 
chemical safety program and (b) this Section. Tenant shall not introduce anything into the sewer system serving the Building 
(x) in violation Applicable Laws. Landlord agrees to reasonably cooperate with Tenant, at no unreimbursed cost to Landlord, in 
order for Tenant to obtain any MWRA permit and wastewater treatment operator license required for Tenant’s operations.
Tenant shall reimburse Landlord within ten (10) business days after demand for any third party costs reasonably incurred by 
Landlord in cooperating with Tenant pursuant to this Section.

13. Rules and Regulations, CC&Rs, Parking Facilities and Common Areas .
     13.1. Tenant shall have the non-exclusive right, in common with others, to use the Common Areas in conjunction with
Tenant’s use of the Premises for the Permitted Use (including without limitation such Common Areas as are reasonably
designated by Landlord for the connection of any equipment located in off-floor mechanical areas that are contained within the
Premises to the applicable occupied floor of the Premises), and such use of the Common Areas and Tenant’s use of the
Premises shall be subject to the rules and regulations and tenant manual governing Alterations, each as adopted by Landlord
Premises shall be subject to the rules and regulations and tenant manual governing Alterations, each as adopted by Landlord
and initially attached hereto as Exhibit F , together with such other reasonable and nondiscriminatory rules and regulations as
are hereafter promulgated by Landlord of which Tenant is given prior written notice (collectively, the “ Rules and Regulations
”), provided, however, that in the case of any conflict between the provisions of this Lease and any such Rules and
Regulations, the provisions of this Lease shall control. Tenant shall faithfully observe and comply with the Rules and
Regulations. Landlord shall use reasonable efforts to enforce the Rules and Regulations against Tenant or any other tenant of
the Building or Property, but shall have no responsibility for any violations thereof. Landlord shall not enforce the Rules and
Regulations in a discriminatory manner against Tenant.

     13.2. This Lease is subject to any recorded covenants, conditions or restrictions on the Property (the “ CC&R ”), to the
Development Approvals (as defined on Exhibit D ), and to any other matters of record, in each case as the same may be
amended, amended and restated, supplemented or otherwise modified from time to time (collectively, the “ Property Operations
Agreements ”; provided that any such amendments, restatements, supplements or modifications do not materially modify
Tenant’s rights or obligations or Landlord’s obligations hereunder. Each of Landlord and Tenant, in the exercise of their
respective rights and the performance of their respective obligations pursuant to this Lease, shall observe and comply with all
requirements of the CC&R and Development Approvals. The CC&R covers certain areas shown on the site plan attached as
Exhibit K , including landscaping, private drives, streets, parks, open space, walkways, sidewalks, the ice skating rink, the water
fountain, the sky bowl and other improvements and appurtenances located thereon and related thereto, including the Building
and other buildings located on the Property thereon, all commonly referred to as “Kendall Square”, and expenses payable by
the Building under the CC&R (which are based on the Lot’s proportionate share of Kendall Square) are included in Operating
Expenses.
  
                                                                 18


     13.3. Tenant shall be permitted access to the Building and Premises on a 24 hour per day, 7 day per week basis, subject to
matters described in Section 41.6 of this Lease and Landlord’s reasonable security measures, and subject to Landlord’s rights
pursuant to this Lease to temporarily prohibit, restrict or limit access to the Building or the Premises in emergency situations if
Landlord determines, in its reasonable discretion, that it is necessary or advisable to do so in order to prevent or protect against
death or injury to persons or damage to property.

      13.4. It is intended that all Rent payable by Tenant to Landlord, which includes all sums, charges, or amounts of whatever
nature to be paid by Tenant to Landlord in accordance with the provisions of this Lease, shall qualify as “rents from real
property” within the meaning of both Sections 512(b)(3) and 856(d) of the Code and the U.S. Department of Treasury 
Regulations promulgated thereunder (the “Regulations”). If Landlord, in its sole discretion, determines that there is any risk that
all or part of any Rent shall not qualify as “rents from real property” for the purposes of Section 512(b)(3) or 856(d) of the Code 
and the Regulations, Tenant agrees (i) to cooperate with Landlord by entering into such amendment or amendments to this 
Lease as Landlord reasonably deems necessary to qualify all Rent as “rents from real property,” and (ii) to permit an assignment 
of this Lease; provided, however, that any adjustments required under this Section shall be made so as to produce the
substantially equivalent (in economic terms) Rent as payable before the adjustment.

      13.5. (a) Tenant shall have a non-exclusive, irrevocable license to use up to a total of 189 unreserved parking spaces (i.e.,
determined by multiplying the Rentable Area of the Premises by 0.0015) from and after the Phase 1 Rent Commencement Date (“ 
Tenant’s Parking Spaces ”) in the underground parking garage on the Property in common with other tenants of the Property at
the market rate for such comparable parking lots in commercial garages in the East Cambridge market, as reasonably determined
by Landlord (as of the date hereof, such rate being Two Hundred Sixty and 00/100 Dollars ($260.00) per parking space per
month), which Tenant shall pay simultaneously with payments of Base Rent as Additional Rent commencing on the Phase 1
Rent Commencement Date unless and except to the extent that Landlord directs Tenant to pay the same to a Garage Operator as
defined below. Upon 30 days’ notice given prior to the Phase 1 Rent Commencement Date, Tenant will have the option of
designating any number of Tenant’s Parking Spaces between the maximum number set forth above and the portion of Tenant’s
Parking Spaces allocable to the Phase 1 Premises (based on Rentable Area) as being licenses as of the Phase 1 Rent
Commencement Date (with the remainder of Tenant’s Parking Spaces being treated as allocable to the Phase 2 Premises).
Tenant’s failure to make any such election prior to the Phase 1 Premises Rent Commencement Date shall be deemed to be an
election to allocate such spaces on a prorated basis between the Phase 1 Premises and Phase 2 Premises. Tenant shall pay for
the license to use Tenant’s Parking Spaces regardless of whether such spaces are in fact used by Tenant; provided, however,
that Tenant shall have the right to terminate its license with respect to any such spaces on 30 days’ prior written notice to
Landlord. Any such termination of Tenant’s license hereunder in whole or in part shall be irrevocable and Landlord shall have
no further right to provide Tenant with spaces for which such rights have terminated, provided that Landlord shall use
reasonable efforts to make additional spaces available to Tenant, subject to availability, on a revocable, month-to-month
  
                                                                 19


basis as reasonably requested by Tenant on at least 30 days’ prior notice (and otherwise on the terms and conditions contained
in this Section 13.5, including the limitation on total spaces licensed by Tenant set forth above). All of Tenant’s Parking Spaces
shall be located in the underground parking structure in the Building (the “ Garage ”), which Garage may be owned or leased by
or to a third-party Garage operator from time to time. The owner or operator of the Garage from time to time is herein referred to
as the “ Garage Operator ,” and the Tenant’s Parking Spaces are sometimes herein referred to as the “ Garage Parking Spaces .” 
Landlord covenants and agrees that if the Garage is conveyed or leased by Landlord to any Garage Operator, such conveyance
shall be subject to a lease, permanent easement or similar instrument by and between Landlord and the Garage Operator so that
the Tenant shall have, from and after the Phase 1 Rent Commencement Date, throughout the Term, the right to use the Garage
Parking Spaces, subject to the terms of this Lease.

           (b) Landlord or the Garage Operator, as applicable, shall have the right, from time to time but not more often than
every two (2) years, to relocate, on a temporary basis (not to exceed thirty (30) days) as may be necessary to effect repairs and 
improvements to the Garage or for other business reasons, parking spaces located in the Garage to another location within 1,000
feet of the Property. Except to the extent resulting from their negligence or willful misconduct and subject to Section 23.7 ,
neither Landlord nor the Garage Operator shall be responsible for money, jewelry, automobiles or other personal property lost in
or stolen from the Garage, regardless of whether such loss or theft occurs when the Garage or other areas therein are locked or
otherwise secured against entry, or liable for any loss, injury or damage to persons using the Garage or automobiles or other
property therein, it being agreed that the use of the Garage and the Tenant’s Parking Spaces shall otherwise be at the sole risk
of Tenant and its employees, visitors and guests. Landlord and the Garage Operator shall have the right from time to time to
promulgate Rules and Regulations regarding the Garage, the Tenant’s Parking Spaces and the use thereof, including, but not
limited to, Rules and Regulations controlling the flow of traffic to and from various parking areas, the angle and direction of
parking and the like, and to implement valet parking. Tenant shall comply with and cause its employees, visitors and guests to
comply with all such Rules and Regulations as well as reasonable additions and amendments thereto.

          (c) Landlord or the Garage Operator, as applicable, may elect to provide parking cards or keys to control access to the
Garage. In such event, Landlord or the Garage Operator shall provide Tenant with one card or key for each Tenant’s Parking
Space that Tenant is leasing hereunder, provided that Landlord or the Garage Operator shall have the right to require Tenant or
its employees to place a reasonable deposit (not to exceed Twenty-Five Dollars ($25.00)) on such access cards or keys and to
pay a reasonable fee for any lost or damaged cards or keys. Tenant, at its sole cost and expense, may obtain extra cards and
keys from Landlord or the Garage Operator, as applicable, if any cards are lost, stolen or destroyed.

      13.6. Landlord reserves the right to modify the Common Areas, including the right to add or remove exterior and interior
landscaping. Tenant acknowledges that Landlord specifically reserves the right to allow the exclusive use of corridors and
restroom facilities located on specific floors to one or more tenants occupying such floors; provided , however, that Tenant
shall not be deprived of the access to or use of the corridors reasonably required to serve the Premises or of restroom facilities
serving each floor upon which any portion of the Premises is located.
  
                                                                 20


    13.7. Subject to the terms of this Lease including the Rules and Regulations and the rights of other tenants of the Building,
Tenant shall have the non-exclusive right to access the freight loading dock, at no additional cost.

14. Property Control by Landlord .
      14.1. Landlord reserves full control over the Building and Property to the extent not inconsistent with Tenant’s use and
enjoyment of the Premises as provided by this Lease. Subject to the foregoing, this reservation includes Landlord’s right to
convert the Building to a condominium form of ownership; add or eliminate a portion of the Property; grant easements and
licenses to third parties; maintain or establish ownership of the Building separate from fee title to the Property; make additions
to or reconstruct portions of the Building; install, use, maintain, repair, replace and relocate for service to the Premises and other
parts of the Building or the Property pipes, ducts, conduits, wires and appurtenant fixtures, wherever located in the Premises,
the Building or elsewhere at the Property; and alter or relocate any other Common Area or facility, including private drives,
lobbies and entrances. Landlord will use reasonable efforts to ensure that any work undertaken in the Premises by Landlord
shall (except in an emergency) be undertaken in a manner that will not unreasonably interfere with Tenant’s operations.

     14.2. Possession of those existing areas of the Premises necessary for utilities, services, safety and operation of the
Building is reserved to Landlord.

     14.3. Tenant shall, at Landlord’s request, promptly execute such further documents, in form and substance reasonably
acceptable to the parties, as may be reasonably appropriate to assist Landlord in the performance of its obligations hereunder;
provided that Tenant need not execute any document that creates additional liability for Tenant or that deprives Tenant of the
quiet enjoyment and use of the Premises as provided for in this Lease.

     14.4. Landlord may, at any and all reasonable times during non-business hours (or during business hours, if (a) with 
respect to Subsections 14(u) through 14.4(y) , Tenant so requests, and (b) with respect to Subsection 14.4(z) , if Landlord so
requests), and upon twenty-four (24) hours’ prior notice ( provided that no time restrictions shall apply or advance notice be
required if an emergency necessitates immediate entry), enter the Premises to (u) inspect the same and to determine whether 
Tenant is in compliance with its obligations hereunder, (v) supply any service Landlord is required to provide hereunder, 
(w) alter, improve or repair any portion of the Building other than the Premises for which access to the Premises is reasonably 
necessary,(x) post notices of nonresponsibility, (y) access the telephone equipment, electrical substation and fire risers and 
necessary,(x) post notices of nonresponsibility, (y) access the telephone equipment, electrical substation and fire risers and 
(z) show the Premises to prospective and actual lenders, purchasers or, during the final year of the Term, tenants. In connection 
with any such alteration, improvement or repair as described in Subsection 14.4(w) , Landlord may erect in the Premises or
elsewhere in the Property scaffolding and other structures reasonably required for the alteration, improvement or repair work to
be performed. Notwithstanding anything to the contrary set forth herein, neither Landlord, nor Landlord’s agents,
representatives, contractors or employees may enter any portion of the Premises reasonably designated from time to time by
Tenant as a
  
                                                                 21


security area (not to exceed 35,000 square feet of Rentable Area in the aggregate, consisting of up to 25,000 square feet of
Rentable Area for a vivarium and up to 10,000 square feet of Rentable Area for a data center) without being accompanied by a
representative of Tenant, except in the case of an emergency, provided that such areas are clearly labeled as such and Landlord
is given at least 10 business days’ prior written notice of the location of such areas. In no event shall Tenant’s Rent abate as a
result of Landlord’s activities pursuant to this Section; provided , however, that all such activities shall be conducted in such a
manner so as to cause as little interference to Tenant as is reasonably possible. Landlord shall at all times retain a key with
which to unlock all of the doors in the Premises. If an emergency necessitates immediate access to the Premises, Landlord may
use whatever force is necessary to enter the Premises, and any such entry to the Premises shall not constitute a forcible or
unlawful entry to the Premises, a detainer of the Premises, or an eviction of Tenant from the Premises or any portion thereof.

15. Quiet Enjoyment . So long as Tenant is not in Default under this Lease, Landlord or anyone acting through or under
Landlord shall not disturb Tenant’s use or occupancy of the Premises or the exercise of Tenant’s rights hereunder in
accordance with this Lease, except as permitted by this Lease.

16. Utilities and Services .
      16.1. Tenant shall pay for all water (including the cost to service, repair and replace reverse osmosis, de-ionized and other
treated water), gas, heat, light, power, telephone, internet service, cable television, other telecommunications and other utilities
supplied to the Premises, together with any fees, surcharges and taxes thereon. Tenant shall, promptly after the Term
Commencement Date as part of the Tenant Improvements, install separate meters, or if separate direct metering is not possible,
sub- or check- meters for any such utilities provided to the Premises (other than those utilities that are used to supply Landlord
services, which are included in Operating Expenses). If any such utility is separately metered, Tenant shall pay the charge
therefore directly to the utility service provider when due. If any such utility is sub- or check-metered from time to time, then
Tenant shall pay for all such charges based on Landlord’s reading of such sub- or check-meters within 30 days after invoice. If,
notwithstanding the foregoing, any such utility is not separately or sub- or check-metered from time to time, then Tenant shall
pay to Landlord within 30 days after invoice for such charges based on Tenant’s Share of such charges provided to the
Building, or Landlord may, at its option, monitor the usage of such utilities by Tenant and charge Tenant with the cost of
purchasing, installing and monitoring such metering equipment, which cost shall be paid by Tenant as Additional Rent. At any
time that Tenant is paying Landlord for the foregoing utilities based on Tenant’s Share, Landlord shall have the right to require
Tenant to pay 1/12th of Landlord’s reasonable estimate of such charges for the applicable calendar year during the term on a
monthly basis, together with payments of Base Rent, and shall reconcile such payments annually. To the extent that Tenant
uses more than Tenant’s Pro Rata Share of the Building of any utilities and such utilities are not separately metered or
submetered, then Tenant shall pay Landlord for Tenant’s Share of such utilities to reflect such excess. In the event that the
Building is less than fully occupied and Tenant is not then separately metered or sub- or check-metered for any utility, Tenant
acknowledges that Landlord may extrapolate utility usage that varies depending on the occupancy of the Building, by dividing
(a) the total cost of utility usage by (b) the Rentable Area of the Lab Building that is occupied, then multiplying (y) the resulting 
quotient by (z) ninety-five
  
                                                                 22


percent (95%) of the total Rentable Area of the Lab Building. Tenant shall pay Tenant’s Share of the product of (y) and (z), 
subject to adjustment based on actual usage as reasonably determined by Landlord; provided , however, that Landlord shall
not recover more than one hundred percent (100%) of such utility costs. 

      16.2. Landlord shall not be liable for, nor shall any eviction of Tenant or default of Landlord result from, the failure to
furnish any utility or service, regardless of the cause, including accident; breakage; strike, lockout or other labor disturbance or
labor dispute of any character; act of terrorism; shortage of materials, which shortage is not unique to Landlord or Tenant, as
the case may be; failure by a third party to deliver gas, oil or another suitable fuel supply; or Landlord’s inability by exercise of
reasonable diligence to obtain gas, oil or another suitable fuel; governmental regulation, moratorium or other governmental
action, inaction or delay; or other causes described in Section 41.6 of this Lease or Landlord’s negligence. In the event of such
failure, Tenant shall not be entitled to termination of this Lease or any abatement or reduction of Rent, nor shall Tenant be
relieved from the operation of any covenant or agreement of this Lease. Notwithstanding anything to the contrary in this Lease,
if, for more than five (5) consecutive business days following written notice to Landlord and, for any reason other than matters 
described in Section 41.6 of this Lease or by an act or omission in violation of this Lease by Tenant or by any negligence of any 
of Tenant’s agents, employees, contractors, invitees, successors or others using the Premises with Tenant’s expressed or
of Tenant’s agents, employees, contractors, invitees, successors or others using the Premises with Tenant’s expressed or
implied permission, the provision of elevator, HVAC, plumbing, or utilities to all or a material portion of the Premises that
Landlord must provide pursuant to this Lease is interrupted, then Tenant’s Base Rent and Operating Expenses (or, to the extent
that less than all of the Premises are affected, a proportionate amount (based on the Rentable Area of the Premises that is
rendered unusable) of Base Rent and Operating Expenses) shall thereafter be abated until the Premises are again usable by
Tenant for the Permitted Use (and the Property Management Fee shall be reduced for such period to reflect any such reduction
in Base Rent); provided , however, that, if Landlord provides substitute elevator, HVAC, plumbing or utilities reasonably
suitable for Tenant’s continued use and occupancy of the Premises for the Permitted Use (e.g., supplying potable water or
portable air conditioning equipment), then neither Base Rent nor Operating Expenses shall be abated so long as Landlord is
diligently pursuing the restoration of such elevator, HVAC, plumbing or utilities. In the event of any interruption of elevator,
HVAC, plumbing, or other utilities that Landlord must provide pursuant to this Lease, regardless of the cause, Landlord shall
diligently pursue the restoration of such elevator, HVAC, plumbing, or other utilities. Notwithstanding anything in this Lease to
the contrary, but subject to Article 24 (which shall govern in the event of a casualty), so long as Landlord is diligently pursuing
the restoration, the provisions of this Section shall be Tenant’s sole recourse and remedy in the event of an interruption of
utilities or Landlord services to the Premises.

     16.3. Tenant shall pay for, prior to delinquency of payment therefor, any services that may be furnished to the Premises
during or, if Tenant occupies the Premises after the expiration or earlier termination of the Term, after the Term, beyond those
services provided by Landlord, including telephone, internet service, cable television and other telecommunications, together
with any fees, surcharges and taxes thereon. Tenant shall pay for such services directly to the supplier of such services.
  
                                                                 23


     16.4. Tenant shall not, without Landlord’s prior written consent, which shall not be unreasonably withheld, delayed or
conditioned, use any device in the Premises (including data processing machines) that will in any way (a) increase the amount 
of ventilation, air exchange, gas, steam, electricity or water required or consumed in the Premises based upon Tenant’s Pro Rata
Share of the Building beyond the existing capacity of the Building usually furnished or supplied for the use set forth in
Section 2.7 or (b) exceed Tenant’s Pro Rata Share of the Building’s capacity to provide such utilities or services.

      16.5. If Tenant shall require utilities or services in excess of those usually furnished or supplied for tenants in similar
spaces in the Building or the Property by reason of Tenant’s equipment or extended hours of business operations, then Tenant
shall first procure Landlord’s consent for the use thereof, which consent Landlord may condition upon the availability of such
excess utilities or services, and Tenant shall pay as Additional Rent an amount equal to Landlord’s actual cost (as may be
reasonably estimated by Landlord) of providing such excess utilities and services to the extent not otherwise paid by Tenant
pursuant to the provisions of Section 16.1, above. 

    16.6. Landlord shall provide water in Common Areas for lavatory and landscaping purposes only, which water shall be
from the local municipal or similar source. Tenant shall not use or consume water provided to the Common Areas for any
purpose other than ordinary or reasonable lavatory purposes.

      16.7. Subject to the provisions of Section 16.2, above, Landlord reserves the right to stop service of the elevator, plumbing, 
HVAC and other utility systems for reasonable periods when Landlord reasonably deems necessary or desirable due to
accident, emergency or the need to make repairs, alterations or improvements, until such repairs, alterations or improvements
shall have been completed. Landlord shall use reasonable efforts to schedule and perform any such repairs, alterations or
improvements outside of business hours to the extent the same will adversely affect Tenant’s ability to conduct its business in
the Premises.

      16.8. Subject to the provisions of this Lease governing Alterations, Tenant, at its sole cost and expense, shall have the
appurtenant right to install and maintain, at no additional charge, one emergency generator, together with connections to
existing Building fuel piping to serve the same (collectively, the “ Generator ”) serving the Premises as reasonably required for
Tenant’s operations in the Premises, subject to Landlord’s reasonable approval with respect to specifications of such generator
and the plans for such installation, in a location within the Rooftop Installation Area or in the Garage as may be mutually agreed
upon between Landlord and Tenant. Tenant shall be responsible for obtaining and maintaining, at its sole cost and expense,
any permits or approvals required in connection with the installation and maintenance of the Generator. The Generator shall be
screened from view in a manner consistent with the standards for a first class office, laboratory and research and development
park in Kendall Square. The installation of the Generator shall be in compliance with applicable laws, codes and ordinances and
shall not interfere with or compromise the integrity of the Building.
  
  
                                                                 24


     16.9. Landlord shall maintain and operate the Building HVAC systems and shall permit Tenant to connect to the same at
the Premises points of connection for Tenant’s use within the Premises and shall furnish HVAC to the Common Areas for
reasonably comfortable occupancy of the same throughout the term of this Lease. To the extent that Tenant requires HVAC
services in excess of those provided by connection to the Building HVAC systems, Tenant shall install and maintain
supplemental HVAC systems in accordance with the provisions of this Lease.

      16.10. For any utilities serving the Premises for which Tenant is billed directly by such utility provider, Tenant agrees to
furnish to Landlord (a) any invoices or statements for such utilities, (b) any other utility usage information received by Tenant 
and reasonably requested by Landlord, and (c) any ENERGY STAR® Statement of Performance (or similar comprehensive utility
usage report (e.g., related to Labs 21), if requested by Landlord) and any other information reasonably requested by Landlord
for the immediately preceding year, all within ninety (90) days after Landlord’s request made no more often than one (1) time per 
year. Tenant shall retain records of utility usage at the Premises, including invoices and statements from the utility provider, for
at least sixty (60) months, or such shorter period of time as may be requested by Landlord. Tenant acknowledges that any utility 
information for the Premises, the Building and the Property may be shared with third parties, including Landlord’s consultants
and Governmental Authorities.

     16.11. Tenant shall have 24-hour access to the freight elevator and freight loading dock serving the Premises in common
with other tenants of the Building at no additional cost (other than to the extent includable in Operating Expenses) and shall
have the right, in common with others, to use the passenger elevators in the Building.

17. Alterations .
      17.1. Tenant shall make no alterations, additions or improvements other in or to the Premises or engage in any
construction, demolition, reconstruction, renovation, or other work (whether major or minor) of any kind in, at, or serving the
Premises (“ Alterations “, which shall include Tenant Improvements) without Landlord’s prior written approval, which approval
Landlord shall not unreasonably withhold, condition or delay; provided , however, that in the event any proposed Alteration
adversely affects (a) any structural portions of the Building, including exterior walls, roof, foundation, foundation systems 
(including barriers and subslab systems), or core of the Building, (b) the exterior of the Building or (c) other than in a minor 
manner not adversely affecting the same, any Building systems, including elevator, plumbing, air conditioning, heating,
electrical, security, life safety and power, then Landlord may withhold its approval with respect thereto in its sole and absolute
discretion. Tenant shall, in making any such Alterations, use only those architects, contractors, suppliers and mechanics of
which Landlord has given prior written approval, which approval shall not be unreasonably withheld, delayed or conditioned. In
seeking Landlord’s approval, Tenant shall provide Landlord, at least fourteen (14) days in advance of any proposed 
construction, with plans, specifications, stamped engineering drawings and calculations by Tenant’s engineer of record or
architect or record, certified as being in accordance with Applicable Laws (including connections to the Building’s structural
system, modifications to the Building’s envelope, non-structural penetrations in slabs or walls, and modifications or tie-ins to
life safety systems), work contracts, requests for laydown areas and such other information concerning the nature and cost of
the Alterations as Landlord may reasonably request. In no event shall Tenant use or Landlord be required to approve any
architects, consultants, contractors, subcontractors or material
  
                                                                25


suppliers that Landlord reasonably believes is likely to cause labor disharmony. Landlord may condition its approval of any
Alterations on Tenant’s removing the same upon the expiration or earlier termination of this Lease or Tenant’s right to
possession of the Premises, at Tenant’s sole cost, provided that Landlord so notifies Tenant at the time that Landlord approves
the plans for such Alterations. Notwithstanding the foregoing, Tenant may make non-structural minor and cosmetic changes to
the Premises (“ Cosmetic Alterations ”) without Landlord’s consent; provided that (y) the cost of any Cosmetic Alterations do 
not exceed Fifty Thousand Dollars ($50,000) in any one instance, (z) such Cosmetic Alterations do not (i) require any structural 
or other substantial modifications to the Premises, (ii) require any changes to, or adversely affect, the Building systems, 
(iii) affect the exterior of the Building or (iv) trigger any requirement under Applicable Laws that would require Landlord to make 
any alteration or improvement to the Building or the Property. Tenant shall give Landlord at least ten (10) days’ prior written
notice of any Cosmetic Alterations.

      17.2. Tenant shall not construct or permit to be constructed partitions or other obstructions that are likely to unreasonably
interfere with free access to mechanical installation or service facilities of the Building or with other tenants’ components
located within the Building, or interfere with the moving of Landlord’s equipment to or from the enclosures containing such
installations or facilities.

     17.3. Tenant shall accomplish any work performed on the Premises or the Building in such a manner as to permit any life
safety systems to remain fully operable at all times.

     17.4. Any work performed on the Premises, the Building or the Property by Tenant or Tenant’s contractors shall be done at
such times and in such manner as Landlord may from time to time reasonably designate. Tenant covenants and agrees that all
work done by Tenant or Tenant’s contractors shall be performed in full compliance with Applicable Laws. Within thirty
(30) days after completion of any Alterations (other than Cosmetic Alterations), Tenant shall provide Landlord with complete 
“as-built” drawing print sets, project specifications and shop drawings, and electronic CADD files on disc (or files in such other
current format in common use as Landlord reasonably approves or requires) showing any changes in the Premises. Any such
“as-built” plans shall show the applicable Alterations as an overlay on the Building as-built plans, to the extent provided by
Landlord to Tenant for such purpose.
    17.5. Before commencing any Alterations, Tenant shall give Landlord at least fourteen (14) days’ prior written notice of the
proposed commencement of such work and shall, if requested by Landlord for any Alterations costing more than $200,000,
when taken together with any related Alterations being made as part of the same project, secure, at Tenant’s own cost and
expense, a performance, completion and lien indemnity bond reasonably satisfactory to Landlord for such work.

      17.6. Tenant shall repair any damage to the Premises caused by Tenant’s removal of any property from the Premises at the
expiration or earlier termination of the Term. The provisions of this Section shall survive the expiration or earlier termination of
this Lease.

     17.7. (a) The Premises shall at all times remain the property of Landlord and shall be surrendered to Landlord upon the
expiration or earlier termination of this Lease.
  
                                                                 26


           (b) All Alterations, Signage, attached equipment, decorations, fixtures, movable laboratory casework and related
appliances, trade fixtures, additions and improvements attached to or built into the Premises, made by either of the Parties
(including all floor and wall coverings, built-in cabinet work and paneling, sinks and related plumbing fixtures, laboratory
benches, exterior venting fume hoods and walk-in freezers and refrigerators, ductwork, conduits, electrical panels and circuits),
shall (unless, prior to such construction or installation, Landlord in writing elects otherwise) become the property of Landlord
upon the expiration or earlier termination of the Term, and shall remain upon and be surrendered with the Premises as a part
thereof.

          (c) Subject to Section 17.7(b) and except as to those items listed on Exhibit G attached hereto (which Exhibit G may be
updated by Tenant from and after the Term Commencement Date, subject to Landlord’s written consent), all Alterations,
together with all additions and accessories thereto, installed in and upon the Premises shall be and remain the property of
Landlord and shall not be moved by Tenant at any time during the Term.

          (d) Notwithstanding any other provision of this Article to the contrary, in no event shall Tenant remove any
improvement from the Premises as to which Landlord contributed payment, including the Tenant Improvements, without
Landlord’s prior written consent, which consent Landlord may withhold in its sole and absolute discretion. Landlord may
require Tenant to remove Specialty Alterations prior to the expiration or earlier termination of the Term; provided, however, that
Tenant shall not be required to remove any Specialty Alterations to the extent the same are shown on Exhibit B-2 attached
hereto. For purposes of this Lease, “ Specialty Alterations ” shall mean Alterations that are not consistent with standard office
or laboratory installations.

           (e) If Tenant shall fail to remove any of its effects from the Premises prior to termination of this Lease, then Landlord
may, at its option, remove the same in any manner that Landlord shall choose and store such effects without liability to Tenant
for loss thereof or damage thereto, and Tenant shall pay Landlord, upon demand, any costs and expenses incurred due to such
removal and storage or Landlord may, at its sole option and without notice to Tenant, sell such property or any portion thereof
at private sale and without legal process for such price as Landlord may obtain and apply the proceeds of such sale against any
(i) amounts due by Tenant to Landlord under this Lease and (ii) any expenses incident to the removal, storage and sale of such 
personal property.

     17.8. Other than with respect to the Tenant Improvements, Tenant shall pay to Landlord an amount equal to three percent
(3%) of the cost to Tenant of all Alterations (other than Tenant Improvements and Cosmetic Alterations) to cover Landlord’s
overhead and expenses for plan review, coordination, scheduling and supervision thereof. For purposes of payment of such
sum, Tenant shall submit to Landlord copies of all bills, invoices and statements covering the costs of such charges,
accompanied by payment to Landlord of the fee set forth in this Section. To the extent Tenant does not perform such remedial
work within a reasonable time after notice from Landlord, and if Landlord thereafter performs the same, Tenant shall reimburse
Landlord for any extra expenses actually incurred by Landlord by reason of faulty work done by Tenant or its contractors, or by
reason of delays caused by such work, or by reason of inadequate clean-up.
  
                                                                 27


     17.9. Within sixty (60) days after final completion of any Alterations performed by Tenant with respect to the Premises, 
Tenant shall submit to Landlord documentation showing the amounts expended by Tenant with respect to such Alterations,
together with supporting documentation reasonably acceptable to Landlord.

     17.10. Tenant shall take, and shall cause its contractors to take, commercially reasonable steps to protect the Premises
during the performance of any Alterations, including covering or temporarily removing any window coverings so as to guard
against dust, debris or damage.

     17.11. Tenant shall require its contractors and subcontractors performing work on the Premises to name the Landlord
Parties and Lenders as additional insureds on their respective general liability insurance policies.
18. Repairs and Maintenance .
     18.1. Landlord shall repair and maintain in good condition the structural and exterior portions and Common Areas of the
Building and the Property, including roofing and covering materials; foundations; exterior walls; plumbing; fire sprinkler
systems (if any); heating, ventilating, air conditioning systems; elevators; and electrical systems installed or furnished by
Landlord consistent with other similar properties in the rental market in which the Building is located, and in full accordance
with Applicable Laws applicable to office and laboratory use generally, without regard for Tenant’s Alterations. The Common
Areas shall be maintained by Landlord in compliance with the ADA except to the extent such compliance would not be required
but for Tenant’s Alterations or its particular use of the Premises, as opposed to the Permitted Uses, generally. Landlord shall
maintain (or provide for the maintenance of) in a neat, attractive and first-class condition all signs, roadways, landscaped areas,
parking areas, sidewalks and entrances areas on the Property.

     18.2. Except for services of Landlord, if any, required by Section 18.1 , Tenant shall at Tenant’s sole cost and expense
maintain and keep the Premises and every part thereof in good condition and repair, excepting damage thereto from ordinary
wear and tear, and damage by casualty or condemnation (except to the extent Tenant is obligated to restore the same) excepted.
Tenant shall, upon the expiration or sooner termination of the Term, surrender the Premises to Landlord in as good a condition
as when received, excepting damage thereto from ordinary wear and tear, and damage by casualty or condemnation (except to
the extent Tenant is obligated to restore the same), and matters for which Tenant is not responsible; and shall, at Landlord’s
request and Tenant’s sole cost and expense, remove all telephone and data systems, wiring and equipment from the Premises,
and repair any damage to the Premises caused thereby. Landlord shall have no obligation to alter, remodel, improve, repair,
decorate or paint the Premises or any part thereof, other than as described in Exhibit B . Tenant shall be responsible, at its sole
cost and expense, for the cleaning of the Premises and Tenant’s removal of its trash, garbage and Hazardous Materials;
provided, however, that Tenant is encouraged to participate in the waste removal and recycling program in place at the
Property. Landlord shall provide a dumpster at the loading dock for Tenant’s use in the disposal of materials (other than
Hazardous Materials and other controlled substances).
  
                                                                 28


      18.3. Landlord shall not be liable for Claims arising out of any failure to make any repairs or to perform any maintenance
that is Landlord’s obligation pursuant to this Lease unless such failure shall persist for an unreasonable time after Tenant
provides Landlord with written notice of the need of such repairs or maintenance (or unless Landlord has actual knowledge of
the need therefor). Tenant waives its rights under Applicable Laws now or hereafter in effect to make repairs at Landlord’s
expense; however, in the event that Landlord fails to make a repair or perform maintenance that is Landlord’s obligation
pursuant to this Lease within applicable notice and cure periods set forth in Section 31.11, and such failure continues for ten 
(10) days after notice thereof to Landlord (with a copy to Landlord’s mortgagee) or such shorter period, if any, as may be
feasible in case of an emergency threatening life or property (such notice to expressly state in bold and prominent print
Tenant’s intention to exercise its rights under this Section), then Tenant, without being under any obligation to do so and
without thereby waiving such default, may remedy such default and perform such repair for the account and at the expense of
Landlord. All reasonable expenditures made by Tenant in connection therewith, including reasonable attorneys’ fees in
instituting, prosecuting or defending any action or proceeding, shall be paid to Tenant by Landlord within thirty (30) days after 
submission by Tenant to Landlord of a reasonably detailed invoice therefor. If Landlord fails to pay such costs to Tenant within
fifteen (15) days following notice from Tenant of such failure, then Tenant shall have the right to recover the same by an 
abatement of Base Rent and the Property Management Fee, provided that such abatement (and the accrual of any interest on
such amounts) shall cease at such time as and to the extent that payment is tendered to Tenant. Notwithstanding the foregoing,
if the amount of the abatement is more than 25% of the aggregate amount of Base Rent due in any month, then the amount
abated in any one month shall not exceed 25% of the Base Rent and the excess amount of the abatement shall be carried forward
with interest at the Default Rate. Tenant’s self-help rights under this paragraph shall be exercised by Tenant only (a) with 
respect to conditions actually existing within the Premises and (b) with respect to conditions that materially affect Tenant’s
ability to use and enjoy the Premises and to conduct Tenant’s operations therein. The provisions of this paragraph may not be
exercised by or on behalf of any subtenants. Any disputes regarding Tenant’s right to have undertaken any such remedy, the
amount of reimbursement claimed by Tenant, or the amount of abatement shall be resolved by arbitration as set forth below.

      The parties shall direct the Boston office of the AAA to appoint an arbitrator who shall have a minimum of ten (10) years’ 
experience in commercial real estate disputes and who shall not be affiliated with either Landlord or Tenant and has not worked
for either party or its affiliates at any time during the prior five (5) years. Both Landlord and Tenant shall have the opportunity 
to present evidence and outside consultants to the arbitrator.

     The arbitration shall be conducted in accordance with the expedited commercial arbitration rules of the AAA insofar as
such rules are not inconsistent with the provisions of this Lease (in which case the provisions of this Lease shall govern). The
cost of the arbitration (exclusive of each party’s witness and attorneys’ fees, which shall be paid by such party) shall be borne
equally by the parties. Any such arbitration shall be commenced within ten (10) days after demand (or, if later, appointment of 
the arbitrator).
  
                                                                 29
     Within ten (10) days after appointment, the arbitrator shall determine whether Tenant was entitled to exercise its self-help
rights and/or the amount of reimbursement to which Tenant is entitled. The arbitrator’s decision shall be final and binding on
the parties.

     18.4. If any excavation shall be made upon land adjacent to or under the Building, or shall be authorized to be made, then at
reasonable times and upon reasonable advance notice, Tenant shall afford to the person causing or authorized to cause such
excavation, license to enter the Premises for the purpose of performing such work as such person shall deem necessary or
desirable to preserve and protect the Building from injury or damage and to support the same by proper foundations, without
any claim for damages or liability against Landlord and without reducing or otherwise affecting Tenant’s obligations under this
Lease. Such work will be done at Landlord’s sole cost, and Landlord shall take such measures as are reasonably and
customarily required to avoid any adverse impacts on Tenant’s use and occupancy of the Premises.

    18.5. This Article relates to repairs and maintenance arising in the ordinary course of operation of the Building and the
Property. In the event of a casualty described in Article 24 , Article 24 shall apply in lieu of this Article. In the event of eminent
domain, Article 25 shall apply in lieu of this Article.

     18.6. Costs incurred by Landlord pursuant to this Article shall constitute Operating Expenses (unless otherwise limited or
excluded under Article 9).

19. Liens .
     19.1. Subject to the immediately succeeding sentence, Tenant shall keep the Premises, the Building and the Property free
from any liens arising out of work performed, materials furnished or obligations incurred by Tenant. Tenant further covenants
and agrees that any mechanic’s lien filed against the Premises, the Building or the Property for work claimed to have been done
for, materials claimed to have been furnished to, or obligations incurred by Tenant shall be discharged or bonded by Tenant
within fifteen (15) days after the filing thereof, at Tenant’s sole cost and expense.

      19.2. Should Tenant fail to discharge or bond against any lien of the nature described in Section 19.1 , Landlord may, at
Landlord’s election, pay such claim or post a bond or otherwise provide security to eliminate the lien as a claim against title, and
Tenant shall immediately reimburse Landlord for the costs thereof as Additional Rent. Tenant shall indemnify, save, defend (at
Landlord’s option and with counsel reasonably acceptable to Landlord) and hold the Landlord Indemnitees harmless from and
against any Claims arising from any such liens, including any administrative, court or other legal proceedings related to such
liens.

      19.3. In the event that Tenant leases or finances the acquisition of office equipment, furnishings or other personal property
of a removable nature utilized by Tenant in the operation of Tenant’s business, Tenant warrants that any Uniform Commercial
Code financing statement shall, upon its face or by exhibit thereto, indicate that such financing statement is applicable only to
removable personal property of Tenant located within the Premises. In no event shall the address of the Premises, the Building
or the Property be furnished on a financing statement without qualifying language as to applicability of the lien only to
removable personal property
  
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located in an identified suite leased by Tenant. Should any holder of a financing statement record or place of record a financing
statement that appears to constitute a lien against any interest of Landlord or against equipment that may be located other than
within an identified suite leased by Tenant, Tenant shall, within ten (10) days after filing such financing statement, cause (a) a 
copy of the Lender security agreement or other documents to which the financing statement pertains to be furnished to
Landlord to facilitate Landlord’s ability to demonstrate that the lien of such financing statement is not applicable to Landlord’s
interest and (b) Tenant’s Lender to amend such financing statement and any other documents of record to clarify that any liens
imposed thereby are not applicable to any interest of Landlord in the Premises, the Building or the Property. Landlord will, on
request by Tenant, execute and deliver any reasonable waiver or subordination of Landlord’s lien that may be required in
connection with any such financing, provided the same does not amend the provisions of this Lease and is reasonably
acceptable to Landlord. Tenant shall be responsible for, and shall reimburse Landlord for, all reasonable attorneys’ fees incurred
by Landlord in connection with any such request.

20. Estoppel Certificate . (a) Tenant shall, within ten (10) business days of receipt of written notice from Landlord, execute, 
acknowledge and deliver a statement in writing substantially in the form attached to this Lease as Exhibit I , or on any other form
reasonably requested by a proposed Lender or purchaser, (a) certifying that this Lease is unmodified and in full force and effect 
(or, if modified, stating the nature of such modification and certifying that this Lease as so modified is in full force and effect)
and the dates to which rental and other charges are paid in advance, if any, (b) acknowledging that there are not, to Tenant’s
knowledge, any uncured defaults on the part of Landlord hereunder, or specifying such defaults if any are claimed, and
(c) setting forth such further factual information with respect to this Lease or the Premises as may be reasonably requested 
thereon. Any such statement may be relied upon by any prospective purchaser or encumbrancer of all or any portion of the real
property of which the Premises are a part. Tenant’s failure to deliver such statement within such the prescribed time, if such
failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which notice shall state, in bold 
failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which notice shall state, in bold 
and prominent print, that failure to reply shall result in a Default under this Section 21(a)), shall, at Landlord’s option, constitute
a Default (as defined below) under this Lease and, in any event, shall be binding upon Tenant that this Lease is in full force and
effect and without modification except as may be represented by Landlord in any certificate prepared by Landlord and delivered
to Tenant for execution. However, no such certificate shall have the effect of amending this Lease, and in the case of any
conflict between this Lease and any certificate, this Lease shall prevail.

           (b) Landlord shall, within ten (10) business days of receipt of written notice from Tenant, execute, acknowledge and 
deliver a statement in writing (a) certifying that this Lease is unmodified and in full force and effect (or, if modified, stating the 
nature of such modification and certifying that this Lease as so modified is in full force and effect) and the dates to which rental
and other charges are paid in advance, if any, (b) acknowledging that there are not, to Landlord’s knowledge, any uncured
defaults on the part of Tenant hereunder, or specifying such defaults if any are claimed, and (c) setting forth such further 
factual information with respect to this Lease or the Premises as may be reasonably requested thereon. However, no such
certificate shall have the effect of amending this Lease, and in the case of any conflict between this Lease and any certificate,
this Lease shall prevail.
  
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21. Hazardous Materials .
      21.1. Tenant shall not cause or permit any Hazardous Materials (as defined below) to be brought upon, kept or used in or
about the Premises, the Building or the Property in violation of Applicable Laws by Tenant or its employees, agents,
contractors or invitees. If Tenant breaches such obligation, or if the presence of Hazardous Materials as a result of such a
breach results in contamination of the Property, any portion thereof, or any adjacent property, or if contamination of the
Premises otherwise occurs during the Term or any extension or renewal hereof or holding over hereunder (other than if such
contamination results from migration of Hazardous Materials from outside the Premises not caused by Tenant or its employees,
agents, contractors or invitees), then Tenant shall indemnify, save, defend (at Landlord’s option and with counsel reasonably
acceptable to Landlord) and hold the Landlord Indemnitees harmless from and against any and all Claims that arise during or
after the Term as a result of such breach or contamination. This indemnification by Tenant includes costs incurred in
connection with any investigation of site conditions or any clean-up, remedial, removal or restoration work required by any
Governmental Authority because of Hazardous Materials present in the air, soil or groundwater above, on or under or about the
Property. Without limiting the foregoing, if the presence of any Hazardous Materials in, on, under or about the Property, any
portion thereof or any adjacent property caused or permitted by Tenant results in any contamination of the Property, any
portion thereof or any adjacent property, then Tenant shall promptly take all actions at its sole cost and expense as are
necessary to return the Property, any portion thereof or any adjacent property to its respective condition existing prior to the
time of such contamination; provided that Landlord’s written approval of such action shall first be obtained, which approval
Landlord shall not unreasonably withhold; and provided , further, that it shall be reasonable for Landlord to withhold its
consent if such actions could have a material adverse long-term or short-term effect on the Property, any portion thereof or any
adjacent property. Notwithstanding any provision of this Lease to the contrary, Tenant shall in no event have any liability (by
way of indemnification or otherwise) for removal or remediation of any Hazardous Materials from the Premises or the Property to
the extent (i) of any condition existing in, on or under the Premises or the Property, as the case may be, on the Term 
Commencement Date, (ii) related to Hazardous Materials that migrate to the Premises following the Term Commencement Date 
from some other part of the Building or Property other than as a result of the acts or omissions of Tenant or any Tenant Party,
or (iii) placed or release in or on the Premises following the Term Commencement Date by Landlord or Landlord’s agents,
contractors and employees.

      21.2. Landlord acknowledges that it is not the intent of this Article to prohibit Tenant from operating its business for the
Permitted Use. Tenant may operate its business according to the custom of Tenant’s industry so long as the use or presence of
Hazardous Materials is strictly and properly monitored in accordance with Applicable Laws. As a material inducement to
Landlord to allow Tenant to use Hazardous Materials in connection with its business, Tenant agrees to deliver to Landlord
(a) so-called MSDS sheets identifying each type of Hazardous Material to be present at the Premises that is subject to
regulation under any environmental Applicable Laws, (b) a list of any and all approvals or permits from Governmental 
Authorities required in connection with the presence of such Hazardous Material at the Premises and (c) correct and complete 
copies of (i) written notices of violations of Applicable Laws actually received by Tenant related to Hazardous Materials at the 
Premises and (ii) plans relating to the installation of any storage tanks to be installed in, on, under or about the Property 
( provided that
  
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installation of storage tanks shall only be permitted after Landlord has given Tenant its written consent to do so, which consent
Landlord may withhold in its reasonable discretion with respect to above-ground storage tanks, and its sole and absolute
discretion with respect to underground storage tanks, if any) and closure plans or any other documents required by any and all
Governmental Authorities for any storage tanks installed in, on, under or about the Property for the closure of any such storage
tanks (collectively, “ Hazardous Materials Documents ”). Tenant shall deliver to Landlord updated Hazardous Materials
Documents (l) no later than thirty (30) days prior to the initial occupancy of any portion of the Premises or the initial placement 
Documents (l) no later than thirty (30) days prior to the initial occupancy of any portion of the Premises or the initial placement 
of equipment anywhere at the Property, (m) if there are any changes to the Hazardous Materials Documents, annually thereafter 
no later than December 31 of each year, and (n) thirty (30) days prior to the initiation by Tenant of any Alterations or changes in 
Tenant’s business that involve any material increase in the types or amounts of Hazardous Materials. For each type of
Hazardous Material listed, the Hazardous Materials Documents shall include (t) the chemical name, (u) the material state (e.g., 
solid, liquid, gas or cryogen), (v) the concentration, (w) the storage amount and storage condition (e.g., in cabinets or not in 
cabinets), (x) the use amount and use condition (e.g., open use or closed use), (y) the location (e.g., room number or other 
identification) and (z) if known, the chemical abstract service number. Notwithstanding anything in this Section to the contrary, 
Tenant shall not be required to provide Landlord with any Hazardous Materials Documents containing information of a
proprietary nature, which Hazardous Materials Documents, in and of themselves, do not contain a reference to any Hazardous
Materials or activities related to Hazardous Materials. Landlord may, at Landlord’s expense, cause the Hazardous Materials
Documents to be reviewed by a person or firm qualified to analyze Hazardous Materials to confirm compliance with the
provisions of this Lease and with Applicable Laws. In the event that a review of the Hazardous Materials Documents indicates
non-compliance with this Lease or Applicable Laws, Tenant shall, at its expense, diligently take steps to bring its storage and
use of Hazardous Materials into compliance. Notwithstanding anything to the contrary herein, in no event shall Tenant
generate, produce, bring upon, use, store or treat Hazardous Materials with a risk category higher than Biosafety Level 2 as 
established by the Department of Health and Human Services (“ DHHS ”) and as further described in the DHHS publication
Biosafety in Microbiological and Biomedical Laboratories (5th Edition) (as it may be or may have been further revised, the “ 
BMBL ”) or such nationally recognized new or replacement standards as may be reasonably selected by Landlord if applicable
to similar facilities in the City of Cambridge).

     21.3. Notwithstanding the provisions of Sections 21.1 , 21.2 or 21.9 , if any proposed transferee, assignee or sublessee of
Tenant is then subject to an outstanding material enforcement order issued by any Governmental Authority in connection with
the use, disposal or storage of Hazardous Materials, then it shall not be unreasonable for Landlord to withhold its consent to
any proposed transfer, assignment or subletting (with respect to any such matter involving a proposed transferee, assignee or
sublessee).

     21.4. At any time, and from time to time, prior to the expiration of the Term, Landlord shall have the right to conduct
appropriate tests of the Property or any portion thereof to demonstrate that Hazardous Materials are present or that
contamination has occurred due to the acts or omissions of Tenant or Tenant’s employees, agents, contractors or invitees
(provided that such tests shall be conducted in a manner that does not unreasonably interrupt or interfere with Tenant’s use of
the Premises for the Permitted Use). Tenant shall pay all reasonable costs of such tests if such tests reveal that Hazardous
Materials exist at the Property in violation of this Lease.
  
                                                                33


     21.5. If underground or other storage tanks storing Hazardous Materials installed or utilized by Tenant are located on the
Premises, or are hereafter placed on the Premises by Tenant (or by any other party, if such storage tanks are utilized by Tenant),
then Tenant shall monitor the storage tanks, maintain appropriate records, implement reporting procedures, properly close any
underground storage tanks, and take or cause to be taken all other steps necessary or required under the Applicable Laws.
Tenant shall have no responsibility or liability for underground or other storage tanks installed by anyone other than Tenant
unless Tenant utilizes such tanks, in which case Tenant’s responsibility for such tanks shall be as set forth in this Section.

     21.6. Tenant shall promptly report to Landlord any actual or suspected presence of mold or water intrusion in the Premises.

     21.7. Tenant’s obligations under this Article shall survive the expiration or earlier termination of this Lease. During any
period of time needed by Tenant or Landlord after the termination of this Lease to complete the removal from the Premises of
any such Hazardous Materials, Tenant shall be deemed a holdover tenant and subject to the provisions of Article 27 below.

     21.8. As used herein, the term “ Hazardous Material ” means, but shall not be limited to, any hazardous substances,
hazardous waste, environmental, biological, chemical, radioactive substances, oil, petroleum products and any waste or
substance, which because of its quantitative concentration, chemical, biological, radioactive, flammable, explosive, infectious or
other characteristics, constitutes or may reasonably be expected to constitute or contribute to a danger or hazard to public
health, safety or welfare or to the environment, including without limitation any asbestos (whether or not friable) and any
asbestos-containing materials, lead paint, waste oils, solvents and chlorinated oils, polychlorinated biphenyls (PCBs), toxic
metals, etchants, pickling and plating wastes, explosives, reactive metals and compounds, pesticides, herbicides, radon gas,
urea formaldehyde foam insulation and chemical, biological and radioactive wastes, or any other similar materials that are
regulated by any Governmental Authority.

      21.9. Notwithstanding anything to the contrary in this Lease, Landlord shall have sole control over the equitable allocation
of fire control areas (as defined in the Uniform Building Code as adopted by the city or municipality(ies) in which the Property is
located (the “ UBC ”)) within the Property for the storage of Hazardous Materials; provided that Tenant shall have the
appurtenant right to use its pro-rata share of such fire control areas made available to tenants on any floor of the Premises
(determined on a floor-by-floor basis based on the ratio of the rentable square footage of the Premises on such floor to the total
rentable square footage of leasable area on such floor as reasonably determined by Landlord on a consistent basis), other than
the first floor of the Building if and to the extent the Premises includes any portion of such floor. Notwithstanding anything to
the contrary in this Lease, the quantity of Hazardous Materials allowed by this Section 21.9 is specific to Tenant and shall not
run with the Lease in the event of a Transfer (as defined in Article 29 ). In the event of a Transfer, if the use of
  
                                                                 34


Hazardous Materials by such new tenant (“ New Tenant ”) is such that New Tenant utilizes fire control areas in the Building in
excess of New Tenant’s Pro Rata Share of the Building, then New Tenant shall, at its sole cost and expense and upon
Landlord’s written request, establish and maintain a separate area of the Premises classified by the UBC as an “H” occupancy
area for the use and storage of Hazardous Materials, or take such other action as is necessary to ensure that its share of the fire
control areas of the Building is not greater than New Tenant’s Pro Rata Share of the Building.

22. Odors and Exhaust . Tenant acknowledges that Landlord would not enter into this Lease with Tenant unless Tenant assured
Landlord that under no circumstances will any other occupants of the Building or the Property (including persons legally
present in any outdoor areas of the Property) be subjected to odors or fumes (whether or not noxious), and that the Building
and the Property will not be damaged by any exhaust, in each case from Tenant’s operations. Landlord and Tenant therefore
agree as follows (and Landlord agrees that it will use commercially reasonable efforts to include substantially similar provisions
regarding odors and exhaust in all lease agreements with other office and/or laboratory tenants or occupants of the Building):

     22.1. Tenant shall not cause or permit (or conduct any activities that would cause) any release of any odors or fumes of
any kind inconsistent with typical first-class office and laboratory use from the Premises.

     22.2. If the Building has a ventilation system that, in Landlord’s judgment, is adequate, suitable, and appropriate to vent
the Premises in a manner that does not release odors affecting any indoor or outdoor part of the Property, Tenant shall vent the
Premises through such system. If Landlord at any time determines that any existing ventilation system is inadequate, or if no
ventilation system exists, Tenant shall in compliance with Applicable Laws vent all fumes and odors from the Premises (and
remove odors from Tenant’s exhaust stream) as Landlord reasonably requires. The placement and configuration of all
ventilation exhaust pipes, louvers and other equipment shall be subject to Landlord’s approval. Tenant acknowledges
Landlord’s legitimate desire to maintain the Property (indoor and outdoor areas) in an odor-free manner, and Landlord may
require Tenant to abate and remove all odors in a manner that goes beyond the requirements of Applicable Laws.

     22.3. Tenant shall, at Tenant’s sole cost and expense, provide commercially reasonable levels of odor eliminators and other
devices (such as filters, air cleaners, scrubbers and whatever other equipment may in Landlord’s judgment be reasonably
necessary or appropriate from time to time) to completely remove, eliminate and abate any odors, fumes or other substances in
Tenant’s exhaust stream that emanate from Tenant’s operations in the Premises. Any work Tenant performs under this Section
shall constitute Alterations.

     22.4. Tenant’s responsibility to remove, eliminate and abate odors, fumes and exhaust caused by operations conducted by,
through or under Tenant shall continue throughout the Term. Landlord’s approval of any Alterations shall not preclude
Landlord from requiring additional measures to eliminate odors, fumes and other adverse impacts of Tenant’s exhaust stream (as
Landlord may designate in Landlord’s reasonable discretion). To the extent reasonably necessary to control odors or fumes
caused by operations conducted by, through or under Tenant, Tenant shall install additional equipment as Landlord reasonably
requires from time to time under the preceding sentence. Such installations shall constitute Alterations.
  
                                                                 35


     22.5. If Tenant fails to install satisfactory odor control equipment within thirty (30) days after Landlord’s demand made at
any time (which may include effective temporary measures so long as permanent measures are taken within thirty (30) days 
thereafter), then Landlord may, without limiting Landlord’s other rights and remedies, require Tenant to cease and suspend any
operations in the Premises that, in Landlord’s determination, cause odors, fumes or exhaust. For example, if Landlord determines
that Tenant’s production of a certain type of product causes odors, fumes or exhaust, and Tenant does not install satisfactory
odor control equipment within thirty (30) days after Landlord’s request, then Landlord may require Tenant to stop producing
such type of product in the Premises unless and until Tenant has installed odor control equipment satisfactory to Landlord.

     22.6. In the event that Tenant installs or maintains any small animal facilities in connection with its laboratory operations in
the Premises, Tenant shall construct and maintain a vacuum-enabled disposal facility for bedding waste and any other noxious
wastes (or such other disposal system reasonably acceptable to Landlord that satisfactorily disposes of such wastes and
controls odors). In no event may any such animal facilities exceed 25,000 square feet of Rentable Area within the Premises.

23. Insurance; Waiver of Subrogation .
     23.1. Landlord shall maintain property insurance for the Building and the Property in amounts equal to full replacement
cost (exclusive of the costs of excavation, foundations and footings, and without reference to depreciation taken by Landlord
upon its books or tax returns), providing protection against any peril generally included within the classification “Special Form,” 
together with insurance against sprinkler damage (if applicable), vandalism and malicious mischief and boiler and machinery
coverage. Landlord, subject to availability thereof, shall further insure, if Landlord deems it appropriate, coverage against flood,
coverage. Landlord, subject to availability thereof, shall further insure, if Landlord deems it appropriate, coverage against flood,
environmental hazard, earthquake, loss or failure of building equipment, rental loss during the period of repairs or rebuilding,
workmen’s compensation insurance and fidelity bonds for employees employed to perform services and may carry such other
insurance coverages, and additional amounts, as are prudent in Landlord’s reasonable determination or are required by
mortgagees from time to time.

      23.2. In addition, Landlord shall carry commercial general liability insurance with a combined single limit of not less than
Five Million Dollars ($5,000,000) for death or bodily injury, or property damage with respect to the Property, to be written on an
occurrence basis. Such insurance required to be carried by Landlord shall be with companies authorized to do business in the
state in which the Property is located and having a rating of not less than policyholder rating of “A-” and financial category
rating of at least Class X in “Best’s Insurance Guide.” 

     23.3. Tenant shall, at its own cost and expense, procure and maintain in effect, beginning on the Term Commencement
Date, and continuing throughout the Term (and occupancy by Tenant, if any, after termination of this Lease) commercial
general liability insurance with limits of not less than Five Million Dollars $5,000,000) per occurrence for death or bodily injury
and for property damage with respect to the Premises (including $100,000 fire legal liability (each loss)).
and for property damage with respect to the Premises (including $100,000 fire legal liability (each loss)).
  
                                                                 36


      23.4. The insurance required to be purchased and maintained by Tenant pursuant to this Lease shall name Landlord, BMR-
PR II LLC, BioMed Realty, L.P., BioMed Realty Trust, Inc., The Prudential Insurance Company of America, BioMed Realty LLC,
and their respective officers, directors, employees, agents, general partners, members, subsidiaries, affiliates and Lenders (“ 
Landlord Parties ”) as additional insureds. Such insurance shall be with companies authorized to do business in the state in
which the Property is located and having a rating of not less than policyholder rating of “A-” and financial category rating of at
least Class X in “Best’s Insurance Guide.” No such additional insured coverage shall be required to protect or insure against
loss arising from the negligence or wrongful act or omissions of an additional insured. Tenant shall obtain for Landlord from the
insurance companies or cause the insurance companies to furnish certificates of coverage to Landlord. No such policy shall be
cancelable or subject to material reduction of coverage except after thirty (30) days’ prior written notice to Landlord (except in
the event of non-payment of premium, in which case ten (10) days written notice shall be given). All such policies shall be 
written as primary policies, not contributing with and not in excess of the coverage that Landlord may carry. Tenant’s policy
may be a “blanket policy” that specifically provides that the amount of insurance shall not be prejudiced by other losses
covered by the policy. Tenant shall, no later than ten (10) days following the expiration of such policies, furnish evidence 
reasonably acceptable to Landlord of Tenant’s procurement of replacement insurance. Tenant agrees that if Tenant does not
take out and maintain such insurance, Landlord may (but shall not be required to) procure such insurance on Tenant’s behalf
and at its cost to be paid by Tenant as Additional Rent.

     23.5. Except for matters arising from the negligence or willful misconduct of Landlord or its agents, contractors and
employees (and then subject to Section 23.7), Tenant assumes the risk of damage to any fixtures, goods, inventory, 
merchandise, equipment and leasehold improvements, and Landlord shall not be liable for injury to Tenant’s business or any
loss of income therefrom, relative to such damage, all as more particularly set forth within this Lease. Tenant shall, at Tenant’s
sole cost and expense, carry such insurance as Tenant desires for Tenant’s protection with respect to personal property of
Tenant or business interruption.

     23.6. In each instance where insurance is to name Landlord Parties as additional insureds, Tenant shall, upon Landlord’s
written request, also designate and furnish certificates evidencing such Landlord Parties as additional insureds to (a) any 
Lender of Landlord holding a security interest in the Building or the Property, (b) the landlord under any lease whereunder 
Landlord is a tenant of the Property if the interest of Landlord is or shall become that of a tenant under a ground lease rather
than that of a fee owner and (c) any management company retained by Landlord to manage the Property. 

     23.7. Landlord and Tenant each hereby waive any and all rights of recovery against the other or against the officers,
directors, employees, agents, general partners, members, subsidiaries, affiliates and Lenders of the other on account of loss or
damage occasioned by such waiving party or its property or the property of others under such waiving party’s control, in each
case to the extent that such loss or damage is insured (or required under this Lease to be insured) against under any fire and
extended coverage insurance policy that either Landlord or Tenant
  
                                                                 37
                                                                  37


may have in force at the time of such loss or damage. Such waivers shall continue so long as their respective insurers so permit.
Any termination of such a waiver shall be by written notice to the other party, containing a description of the circumstances
hereinafter set forth in this Section. Landlord and Tenant, upon obtaining the policies of insurance required or permitted under
this Lease, shall give notice to the insurance carrier or carriers that the foregoing mutual waiver of subrogation is contained in
this Lease. If such policies shall not be generally obtainable from reputable insurers with such waiver or shall be so obtainable
only at a premium over that chargeable without such waiver, then the party seeking such policy shall notify the other of such
conditions, and the party so notified shall have ten (10) days thereafter to either (a) procure such insurance with companies 
reasonably satisfactory to the other party or (b) agree to pay such additional premium (in Tenant’s case, in the proportion that
the area of the Premises bears to the insured area). If the parties do not accomplish either (a) or (b), then this Section shall have 
no effect during such time as such policies shall not be obtainable or the party in whose favor a waiver of subrogation is
desired refuses to pay the additional premium. If such policies shall at any time be generally unobtainable from reputable
insurers, but shall be subsequently obtainable, then neither party shall be subsequently liable for a failure to obtain such
insurance until a reasonable time after notification thereof by the other party. If the release of either Landlord or Tenant, as set
forth in the first sentence of this Section, shall contravene Applicable Laws, then the liability of the party in question shall be
deemed not released but shall be secondary to the other party’s insurer.

     23.8. Landlord may require insurance policy limits required under this Lease to be raised from time to time to conform with
reasonable requirements of Landlord’s Lender or to bring coverage limits to reasonable levels then being required of other
similar office and laboratory tenants within Kendall Square, generally.

     23.9. Any costs incurred by Landlord pursuant to this Article shall constitute a portion of Operating Expenses to the extent
not otherwise expressly excluded pursuant to the provisions of Section 9.1(c). 

24. Damage or Destruction .
      24.1. In the event of a partial destruction of (a) the Premises or (b) Common Areas of the Building or the Property ((a) and 
(b) together, the “ Affected Areas ”) by fire or other perils covered by special form insurance not exceeding twenty-five percent
(25%) of the full insurable value thereof, and provided that the damage thereto is such that the Affected Areas may be repaired,
reconstructed or restored within a period of one (1) year from the adjustment of such casualty loss with the insurer, and 
Landlord shall receive insurance proceeds sufficient to cover the cost of such repairs, reconstruction and restoration (except for
any commercially reasonable deductible amount provided by Landlord’s policy, which deductible amount, if paid by Landlord,
shall constitute an Operating Expense, and provided that Landlord shall have complied with the requirements of Section 23.1), 
then Landlord shall commence and proceed diligently with the work of repair, reconstruction and restoration of the Affected
Areas and this Lease shall continue in full force and effect. If Landlord does not receive insurance proceeds sufficient to cover
the cost of such repairs, reconstruction and restoration, despite Landlord’s diligent and commercially reasonable efforts, and
neither Landlord nor any Mortgagee has commenced such restoration within three (3) months following 
  
                                                                  38
adjustment of such casualty loss with the insurer, then Tenant may, until any such restoration commences, terminate this Lease
by giving at least thirty (30) days’ prior written notice thereof to Landlord and such termination shall be effective on the date
specified if such replacement has not then commenced.

       24.2. In the event of any damage to or destruction of the Building or the Property other than as described in Section 24.1 ,
Landlord may elect to repair, reconstruct and restore the Building or the Property, as applicable, in which case this Lease shall
continue in full force and effect. If Landlord elects not to repair, reconstruct and restore the Building or the Property, as
applicable, in accordance with Section 24.3, below, then this Lease shall terminate as of the date of such damage or destruction. 
In the event of any damage or destruction (regardless of whether such damage is governed by Section 24.1 or this Section), if
(a) in Landlord’s determination as set forth in the Damage Repair Estimate (as defined below), the Affected Areas cannot be
repaired, reconstructed or restored within twelve (12) months after the date that repairs would commence (provided such 
Damage Repair Estimate is provided to Tenant within 60 days following the date of such damage or destruction), or (b) subject 
to Section 24.6 , the Affected Areas are not actually repaired, reconstructed and restored within the longer of (I) twelve 
(12) months after the date that repairs were to commence as estimated in the Damage Repair Estimate or (II) the period estimated 
for repair as set forth in the Damage Repair Estimate, then Tenant shall have the right to terminate this Lease, effective as of the
date of such damage or destruction, by delivering to Landlord its written notice of termination (a “ Termination Notice ”)
(y) with respect to Subsection 24.2(a) , no later than fifteen (15) days after Landlord delivers to Tenant Landlord’s Damage
Repair Estimate and (z) with respect to Subsection 24.2(b) , no later than fifteen (15) days after such period (as the same may be 
extended pursuant to Section 24.6 ) expires. If Tenant provides Landlord with a Termination Notice pursuant to Subsection 24.2
(z) , Landlord shall have an additional thirty (30) days after receipt of such Termination Notice to complete the repair, 
reconstruction and restoration. If Landlord does not complete such repair, reconstruction and restoration within such thirty
(30) day period, then Tenant may terminate this Lease by giving Landlord written notice within two (2) business days after the 
expiration of such thirty (30) day period. If Landlord does complete such repair, reconstruction and restoration within such 
thirty (30) day period, then this Lease shall continue in full force and effect. If Landlord does not so give a notice of its election 
not to repair, then Landlord shall be deemed to have elected to repair the Property and Premises as aforesaid.

     24.3. As soon as reasonably practicable, but in any event within sixty (60) days following the date of damage or 
destruction, Landlord shall notify Tenant of Landlord’s good faith estimate of the period of time in which the repairs,
reconstruction and restoration will be completed (the “ Damage Repair Estimate ”), which estimate shall be based upon the
opinion of a contractor reasonably selected by Landlord and experienced in comparable repair, reconstruction and restoration of
similar buildings. Additionally, Landlord shall give written notice to Tenant within sixty (60) days following the date of damage 
or destruction of its election not to repair, reconstruct or restore the Building or the Property, as applicable.

      24.4. Upon any termination of this Lease under any of the provisions of this Article, the parties shall be released thereby
without further obligation to the other from the date possession of the Premises is surrendered to Landlord, except with regard
to (a) items occurring prior to the damage or destruction and (b) provisions of this Lease that, by their express terms, survive 
the expiration or earlier termination hereof.
  
                                                                  39
      24.5. In the event of repair, reconstruction and restoration as provided in this Article, all Rent to be paid by Tenant under
this Lease shall be abated proportionately based on the extent to which Tenant’s use of the Premises is impaired during the
period of such repair, reconstruction or restoration (and the Property Management Fee shall be reduced based on such
reduction in Base Rent, if any), unless Landlord provides Tenant with other space during the period of repair, reconstruction
and restoration that, in Tenant’s reasonable opinion, is suitable for the temporary conduct of Tenant’s office and/or laboratory
operations. Tenant acknowledges that, given such abatement, Tenant will not have any claim against its own insurer to recover
rent that would otherwise have been payable during the period of such abatement.

     24.6. Notwithstanding anything to the contrary contained in this Article, should Landlord be delayed or prevented from
completing the repair, reconstruction or restoration of the damage or destruction to the Premises after the occurrence of such
damage or destruction by matters described in Section 41.6 of this Lease or delays caused by Tenant or its employees, agents, 
contractors or invitees, then the time for Landlord to commence or complete repairs, reconstruction and restoration shall be
extended on a day-for-day basis.

      24.7. If Landlord is obligated to or elects to repair, reconstruct or restore as herein provided, then Landlord shall be
obligated to make such repairs, reconstruction or restoration only with regard to (a) those portions of the Premises that were 
originally provided at Landlord’s expense (i.e. excluding Alterations, other than to the extent funded by the TI Allowance) and
(b) the Common Area portion of the Affected Areas. The repairs, reconstruction or restoration of improvements not originally 
provided by Landlord or at Landlord’s expense shall be the obligation of Tenant. Tenant alone shall be entitled to settle, adjust
and receive the proceeds of any insurance policies held by Tenant, and to use the proceeds thereof as Tenant deems
appropriate for the restoration of Tenant’s Alterations. In the event Tenant has elected to upgrade certain improvements from
the Building Standard, Landlord shall, upon the need for replacement due to an insured loss, provide only the Building
Standard, unless Tenant again elects to upgrade such improvements and pay any incremental costs related thereto, except to
the extent that excess insurance proceeds, if received, are adequate to provide such upgrades, in addition to providing for basic
repairs, reconstruction and restoration of the Premises, the Building and the Property.

     24.8. Notwithstanding anything to the contrary contained in this Article, Landlord shall not have any obligation
whatsoever to repair, reconstruct or restore the Premises if the damage resulting from any casualty covered under this Article
occurs during the last twelve (12) months of the Term or any extension thereof, or to the extent that insurance proceeds are not 
available therefor.

    24.9. Landlord’s obligation, should it elect or be obligated to repair, reconstruct or restore, shall be limited to the Affected
Areas. Tenant shall, at its expense, replace or fully repair all of Tenant’s personal property and any Alterations installed by
Tenant existing at the time of such damage or destruction. If Affected Areas are to be repaired, reconstructed or restored in
  
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accordance with the foregoing, Landlord shall make available to Tenant any portion of insurance proceeds it receives that are
allocable to the Alterations constructed by Tenant pursuant to this Lease; provided Tenant is not then in monetary default of
which Tenant shall have received written notice in accordance with this Lease or otherwise in Default under this Lease, and
subject to the reasonable requirements of any Lender of Landlord as to the method of disbursement of such proceeds.

25. Eminent Domain .
     25.1. In the event (a) the whole of all Affected Areas or (b) such part thereof as shall substantially interfere (in Tenant’s
reasonable determination, made in good faith) with Tenant’s reasonable, efficient and beneficial use and occupancy of all or a
substantial portion of the Premises for the Permitted Use shall be taken for any public or quasi-public purpose by any lawful
power or authority by exercise of the right of appropriation, condemnation or eminent domain, or sold to prevent such taking,
Tenant or Landlord may terminate this Lease effective as of the date possession is required to be surrendered to such authority,
except with regard to (y) items occurring prior to the taking and (z) provisions of this Lease that, by their express terms, survive 
the expiration or earlier termination hereof.

     25.2. In the event of a partial taking of (a) the Building or the Property or (b) drives, walkways or parking areas serving the 
Building or the Property for any public or quasi-public purpose by any lawful power or authority by exercise of right of
appropriation, condemnation, or eminent domain, or sold to prevent such taking, then, without regard to whether any portion of
the Premises occupied by Tenant was so taken, Landlord may elect to terminate this Lease (except with regard to (y) items 
occurring prior to the taking and (z) provisions of this Lease that, by their express terms, survive the expiration or earlier 
termination hereof) as of such taking if such taking is, in Landlord’s sole opinion, of a material nature such as to make it
uneconomical to continue use of the unappropriated portion for purposes of renting office or laboratory space.
Notwithstanding the foregoing, Landlord may only exercise its option to terminate this Lease as described in this Section 25.2 if 
Landlord also terminates the leases of tenants similarly affected by such taking.

     25.3. Tenant shall be entitled to any award that is specifically awarded as compensation for (a) the taking of Tenant’s
personal property, trade fixtures and equipment that was installed at Tenant’s expense and (b) the costs of Tenant moving to a 
new location. Except as set forth in the previous sentence, any award for such taking shall be the property of Landlord.

     25.4. If, upon any taking of the nature described in this Article, this Lease continues in effect, then Landlord shall promptly
proceed to restore the Affected Areas to substantially their same condition prior to such partial taking. To the extent such
restoration is infeasible, as determined by Landlord in its reasonable discretion, the Rent shall be decreased proportionately to
reflect the loss of any portion of the Premises no longer available to Tenant (and the Property Management Fee shall be
reduced to reflect any decrease in Base Rent resulting therefrom).
  
                                                                 41


26. Surrender .
     26.1. At least 30 days prior to Tenant’s surrender of possession of any part of the Premises, Tenant shall provide Landlord
with (a) a facility decommissioning and Hazardous Materials closure plan for the Premises (“ Exit Survey ”) prepared by an
independent third party reasonably acceptable to Landlord, (b) written evidence of all appropriate governmental releases 
obtained by Tenant in accordance with Applicable Laws, including laws pertaining to the surrender of the Premises, and
(c) proof that the Premises have been decommissioned in accordance with American National Standards Institute (“ ANSI ”)
Publication Z9.11-2008 (entitled “Laboratory Decommissioning”) or any successor standards published by ANSI or any
successor organization (or, if ANSI and its successors no longer exist, a similar entity publishing similar standards). In addition,
Tenant agrees to remain responsible after the surrender of the Premises for the remediation of any recognized environmental
conditions set forth in the Exit Survey and compliance with any recommendations set forth in the Exit Survey. Tenant’s
obligations under this Section shall survive the expiration or earlier termination of this Lease.

     26.2. No surrender of possession of any part of the Premises shall release Tenant from any of its obligations hereunder,
unless such surrender is accepted in writing by Landlord.

     26.3. The voluntary or other surrender of this Lease by Tenant shall not effect a merger with Landlord’s fee title or
leasehold interest in the Premises, the Building or the Property, unless Landlord consents in writing, and shall, at Landlord’s
option, operate as an assignment to Landlord of any or all subleases.

     26.4. The voluntary or other surrender of any ground or other underlying lease that now exists or may hereafter be
executed affecting the Building or the Property, or a mutual cancellation thereof or of Landlord’s interest therein by Landlord
and its lessor shall not effect a merger with Landlord’s fee title or leasehold interest in the Premises, the Building or the Property
and shall, at the option of the successor to Landlord’s interest in the Building or the Property, as applicable, operate as an
assignment of this Lease.

27. Holding Over .
     27.1. If, with Landlord’s prior written consent, Tenant holds possession of all or any part of the Premises after the Term,
Tenant shall become a tenant from month to month after the expiration or earlier termination of the Term, and in such case
Tenant shall continue to pay (a) Base Rent in accordance with Article 7 , as adjusted in accordance with Article 8 , and (b) any 
amounts for which Tenant would otherwise be liable under this Lease if the Lease were still in effect, including payments for
Tenant’s Share of Operating Expenses. Any such month-to-month tenancy shall be subject to every other term, covenant and
agreement contained herein.

      27.2. Notwithstanding the foregoing, if Tenant remains in possession of the Premises after the expiration or earlier
termination of the Term without Landlord’s prior written consent, (a) Tenant shall become a tenant at sufferance subject to the 
terms and conditions of this Lease, except that the monthly rent shall be equal to one hundred fifty percent (150%) of the Rent 
in effect during the last thirty (30) days of the Term, and (b) Tenant shall be liable to Landlord for any and all damages suffered 
by Landlord as a result of the length of such holdover that exceeds thirty (30) days, including any lost rent or consequential, 
special and indirect damages.
  
                                                                  42


    27.3. Acceptance by Landlord of Rent after the expiration or earlier termination of the Term shall not result in an extension,
renewal or reinstatement of this Lease.
renewal or reinstatement of this Lease.

     27.4. The foregoing provisions of this Article are in addition to and do not affect Landlord’s right of reentry or any other
rights of Landlord hereunder or as otherwise provided by Applicable Laws.

28. Indemnification and Exculpation .
      28.1. Except to the extent any matter arises from or as a result of the negligent or willful and wrongful act or omission of
Landlord or its agents, employees or contractors, and subject always to Section 23.7 and 28.2 and any subrogation provisions 
contained in the Work Letter, Tenant agrees to indemnify, save, defend (with counsel reasonably acceptable to Landlord,
unless required to be approved by Tenant’s insurer) and hold the Landlord Indemnitees harmless from and against any and all
Claims arising from injury or death to any person or damage to any property (x) occurring within or about the Premises or, 
(y) arising out of Tenant’s or Tenant’s employees’, agents’, contractors’ or invitees’ negligent or wrongful use or occupancy of
the Building or the Property (other than the Premises). Subject to Sections 23.7 and 28.2 and any subrogation provisions
contained in the Work Letter, Landlord agrees to indemnify, save, defend (at Tenant’s option and with counsel reasonably
acceptable to Tenant) and hold Tenant and its employees, agents and contractors harmless from and against any and all Claims
arising from injury or death to any person or damage to any property occurring within or about the Premises, the Building or the
Property arising out of the gross negligence or willful misconduct of Landlord or its agents, employees or contractors
misconduct.

     28.2. Notwithstanding anything in this Lease to the contrary, unless any such loss is due to the negligent or willful
misconduct of Landlord or its agents, employees or contractors with respect to any repair (or failure to make a repair) that
Landlord is responsible to make for an unreasonable period of time, Landlord shall not be liable to Tenant for and Tenant
assumes all risk of (a) damage or losses caused by fire, electrical malfunction, gas explosion, water damage of any type 
(including broken water lines, malfunctioning fire sprinkler systems, roof leaks or stoppages of lines), and (b) damage to 
personal property. Tenant further waives any claim for injury to Tenant’s business or loss of income relating to any such
damage or destruction of personal property as described in this Section. Notwithstanding anything in the foregoing or this
Lease to the contrary, except (x) as otherwise expressly provided herein, (y) as may be provided by Applicable Laws or (z) in the 
event of Tenant’s breach of Article 21 or Section 26.1 , in no event shall Landlord or Tenant be liable to the other for any
consequential, special or indirect damages arising out of this Lease.

      28.3. Landlord shall not be liable for any damages arising from any act, omission or neglect of any other tenant in the
Building or the Property, or of any other unaffiliated third party (provided that nothing in this Section 28.3 shall be deemed to 
relieve Landlord of its repair and maintenance obligations as set forth in this Lease).

     28.4. Tenant acknowledges that security devices and services, if any, while intended to deter crime, may not in given
instances prevent theft or other criminal acts. Landlord shall not be liable for injuries or losses caused by criminal acts of third
parties, and Tenant assumes the
  
                                                                  43
risk that any security device or service may malfunction or otherwise be circumvented by a criminal. If Tenant desires protection
against such criminal acts, then Tenant shall, at Tenant’s sole cost and expense, obtain appropriate insurance coverage.

     28.5. The provisions of this Article shall survive the expiration or earlier termination of this Lease.

29. Assignment or Subletting .
      29.1. Except as hereinafter expressly permitted, Tenant shall not, either voluntarily or by operation of Applicable Laws,
directly or indirectly sell, hypothecate, assign, pledge, encumber or otherwise transfer this Lease, or sublet the Premises (each, a
“ Transfer ”), without Landlord’s prior written consent. Notwithstanding the foregoing, Tenant shall have the right to Transfer
without Landlord’s prior written consent the Premises or any part thereof to (i) any person that as of the date of determination 
(and is contemplated to so remain), controls, is controlled by, or is under common control with Tenant (“ Tenant’s Affiliate ”),
or (ii) any successor to Tenant by merger, consolidation, acquisition of all or substantially all of Tenant’s assets or ownership
interests, or corporate reorganization, provided that (x) such merger, consolidation, acquisition of all or substantially all of 
Tenant’s assets or ownership interests, or corporate reorganization is for a good business purpose and not principally for the
purpose of transferring this Lease in violation of this provision, (y) the resulting tenant under this Lease has a net worth at least 
equal to or greater than $500,000,000 , and (z) any such successor to Tenant agrees in writing to assume all of the terms, 
covenants and conditions of this Lease arising after the effective date of such assignment (together with Transfers to Tenant’s
Affiliates, “ Exempt Transfers ”). In the event of an Exempt Transfer, Tenant shall notify Landlord in writing at least ten
(10) days prior to the effectiveness of such Exempt Transfer and otherwise comply with the requirements of this Lease regarding 
such Transfer. For purposes of Exempt Transfers, “control” requires both (a) owning (directly or indirectly) more than fifty 
percent (50%) of the stock or other equity interests of another person and (b) possessing, directly or indirectly, the power to 
direct or cause the direction of the management and policies of such person. In no event shall Tenant perform a Transfer (other
than an Exempt Transfer) to or with an entity that is a tenant at the Property or that is in then-active discussions or negotiations
(as evidenced by exchanges of proposals or communications) with Landlord or an affiliate of Landlord to lease premises at the
Property or a property owned by Landlord or an affiliate of Landlord in Kendall Square so long as Landlord or such affiliate has
comparable space available for lease in Kendall Square for a comparable term, as reasonably determined by Landlord.
Notwithstanding anything to the contrary contained in this Section 29.1 , so long as Tenant’s stock is publicly traded on a
nationally recognized exchange, neither a public offering of Tenant’s stock nor the transfer from time to time of Tenant’s stock
over a nationally recognized exchange shall not be deemed a Transfer and shall not require Landlord’s consent.

     29.2. In the event Tenant desires to effect a Transfer, then, at least fifteen (15) but not more than ninety (90) days prior to 
the date when Tenant desires the assignment or sublease to be effective (the “ Transfer Date ”), Tenant shall provide written
notice to Landlord (the “ Transfer Notice ”) containing information (including references) concerning the character of the
proposed transferee, assignee or sublessee; the
  
                                                                  44


Transfer Date; any ownership or commercial relationship between Tenant and the proposed transferee, assignee or sublessee;
and the consideration and all other material terms and conditions of the proposed Transfer, all in such detail as Landlord shall
reasonably require.

      29.3. Landlord, in determining whether consent should be given to a proposed Transfer, may give consideration to (a) the 
financial strength of such transferee, assignee or sublessee (notwithstanding Tenant remaining liable for Tenant’s
performance), and (b) any change in use that such transferee, assignee or sublessee proposes to make in the use of the 
Premises and (c) Landlord’s desire to exercise its rights under Section 29.8 (to the extent applicable) to cancel this Lease. In no
event shall Landlord be deemed to be unreasonable for declining to consent to a Transfer to a transferee, assignee or sublessee
of poor reputation, lacking financial qualifications or seeking a change in the Permitted Use, or jeopardizing directly or indirectly
the status of Landlord or any of Landlord’s affiliates as a Real Estate Investment Trust under the Internal Revenue Code of 1986
(as the same may be amended from time to time, the “ Revenue Code ”). Notwithstanding anything contained in this Lease to
the contrary, (w) no Transfer shall be consummated on any basis such that the rental or other amounts to be paid by the 
occupant, assignee, manager or other transferee thereunder would be based, in whole or in part, on the income or profits
derived by the business activities of such occupant, assignee, manager or other transferee; (x) Tenant shall not furnish or 
render any services to an occupant, assignee, manager or other transferee with respect to whom transfer consideration is
required to be paid, or manage or operate the Premises or any capital additions so transferred, with respect to which transfer
consideration is being paid; (y) Tenant shall not consummate a Transfer with any person in which Landlord owns an interest, 
directly or indirectly (by applying constructive ownership rules set forth in Section 856(d)(5) of the Revenue Code); and 
(z) Tenant shall not consummate a Transfer with any person or in any manner that could cause any portion of the amounts 
received by Landlord pursuant to this Lease or any sublease, license or other arrangement for the right to use, occupy or
possess any portion of the Premises to fail to qualify as “rents from real property” within the meaning of Section 856(d) of the 
Revenue Code, or any similar or successor provision thereto or which could cause any other income of Landlord to fail to
qualify as income described in Section 856(c)(2) of the Revenue Code. 

     29.4. The following are conditions precedent to a Transfer or to Landlord considering a request by Tenant to a Transfer:

          (a) Tenant shall remain fully liable under this Lease during the unexpired Term;

          (b) Tenant shall reimburse Landlord for Landlord’s reasonable and actual third party costs and expenses, including
reasonable attorneys’ fees, charges and disbursements incurred in connection with the review, processing and documentation
of such request;

           (c) If Tenant’s transfer of rights or sharing of the Premises (other than with respect to any Exempt Transfer) provides
for the receipt by, on behalf of or on account of Tenant of any consideration of any kind whatsoever (including a premium
rental for a sublease or lump sum payment for an assignment, but excluding Tenant’s reasonable costs in negotiating the
sublease or assignment and marketing and subleasing the Premises, and in preparing the applicable portion of the Premises for
occupancy by such subtenant or assignee) in excess of the
  
                                                                 45


rental and other charges due to Landlord under this Lease, Tenant shall pay fifty percent (50%) of all of such excess to 
rental and other charges due to Landlord under this Lease, Tenant shall pay fifty percent (50%) of all of such excess to 
Landlord, after making deductions for any reasonable legal and marketing expenses, tenant improvement funds expended by
Tenant, alterations, architectural/engineering costs, brokerage commissions, attorneys’ fees and free rent actually paid by
Tenant. If such consideration consists of cash paid to Tenant, payment to Landlord shall be made upon receipt by Tenant of
such cash payment;

          (d) The proposed transferee, assignee or sublessee shall agree that, in the event Landlord gives such proposed
transferee, assignee or sublessee notice that Tenant is in Default under this Lease, such proposed transferee, assignee or
sublessee shall thereafter make all payments otherwise due Tenant directly to Landlord, which payments shall be received by
Landlord without any liability being incurred by Landlord, except to credit such payment against those due by Tenant under
this Lease, and any such proposed transferee, assignee or sublessee shall agree to attorn to Landlord or its successors and
assigns should this Lease be terminated for any reason; provided , however, that in no event shall Landlord or its Lenders,
successors or assigns be obligated to accept such attornment;

            (e) Landlord’s consent to any such Transfer shall be effected on Landlord’s reasonable forms;

            (f) Tenant shall not then be in Default hereunder;

            (g) Such proposed transferee, assignee or sublessee’s use of the Premises shall be the same as the Permitted Use;

          (h) Landlord shall not be bound by any provision of any agreement pertaining to the Transfer, except for Landlord’s
written consent to the same;

            (i) Tenant shall pay all transfer and other taxes (including interest and penalties) assessed or payable for any
Transfer;

            (j) Landlord’s consent (or waiver of its rights) for any Transfer shall not waive Landlord’s right to consent to any later
Transfer;

          (k) Tenant shall deliver to Landlord one executed copy of any and all written instruments evidencing or relating to the
Transfer; and

          (l) If such Transferee shall be permitted to engage in any laboratory use, a list of Hazardous Materials (as defined in
Section 21.7 ), certified by the proposed transferee, assignee or sublessee to be true and correct, that the proposed transferee,
assignee or sublessee intends to use or store in the Premises. Additionally, Tenant shall deliver to Landlord, on or before the
date any proposed transferee, assignee or sublessee takes occupancy of the Premises, all of the items relating to Hazardous
Materials of such proposed transferee, assignee or sublessee as described in Section 21.2 .

     29.5. Any Transfer that is not in compliance with the provisions of this Article shall be void and shall, at the option of
Landlord, terminate this Lease. Tenant shall cause each Transferee (including any transferee under an Exempt Transfer), for the
benefit of Landlord, to
  
                                                                  46
reaffirm, on behalf of such Transferee, the representations of, and to otherwise comply with the obligations set forth in,
Section 37, and it shall be reasonable for Landlord to refuse to consent to a Transfer in the absence of such reaffirmation and 
compliance. Tenant agrees that breach of the representations and warranties set forth in Section 37, shall at Landlord’s election
be a default under this Lease for which there shall be no cure.
be a default under this Lease for which there shall be no cure.

     29.6. The consent by Landlord to a Transfer shall not relieve Tenant or proposed transferee, assignee or sublessee from
obtaining Landlord’s consent to any further Transfer, nor shall it release Tenant or any proposed transferee, assignee or
sublessee of Tenant from full and primary liability under this Lease.

     29.7. Notwithstanding any Transfer, Tenant shall remain fully and primarily liable for the payment of all Rent and other
sums due or to become due hereunder, and for the full performance of all other terms, conditions and covenants to be kept and
performed by Tenant. The acceptance of Rent or any other sum due hereunder, or the acceptance of performance of any other
term, covenant or condition thereof, from any person or entity other than Tenant shall not be deemed a waiver of any of the
provisions of this Lease or a consent to any Transfer.

      29.8. If Tenant delivers to Landlord a Transfer Notice indicating a desire to transfer this Lease to a proposed transferee,
assignee or sublessee (other than with respect to any Exempt Transfer or sublets not exceeding the lesser of one full floor and
40% of the Premises in the aggregate) for at least 85% of the then remaining term (in the case of a sublease), then Landlord shall
have the option, exercisable by giving notice to Tenant at any time within ten (10) days after Landlord’s receipt of such Transfer
Notice, to terminate (in each case (a) as of the date specified in the Transfer Notice as the Transfer Date, and (b) except for 
those provisions that, by their express terms, survive the expiration or earlier termination hereof) this Lease (y) in its entirety, if 
such Transfer Notice relates to an assignment of this Lease or a sublease of 80% or more of the Premises, or (z) solely with 
respect to the portion of the Premises subject to such Transfer Notice, if such Transfer Notice relates to a sublease of less than
80% of the Premises but at least one full floor of the Building. If Landlord exercises such option, then Tenant shall have the
right to withdraw such Transfer Notice by delivering to Landlord written notice of such election within five (5) business days 
after Landlord’s delivery of notice electing to exercise Landlord’s option to terminate this Lease. In the event Tenant withdraws
the Transfer Notice as provided in this Section, this Lease shall continue in full force and effect in its entirety. No failure of
Landlord to exercise its option to terminate this Lease shall be deemed to be Landlord’s consent to a proposed Transfer. If this
Lease shall be terminated or released as to a portion of the Premises only pursuant to clause (z), above, Base Rent, the Property
Management Fee, Tenant’s Pro Rata Share and the number of parking spaces for Tenant’s use, shall be readjusted
proportionately according to the ratio that the Rentable Area in the portion of the Premises surrendered compares to the
Rentable Area of Tenant’s remaining Premises, and Landlord and Tenant shall enter into a suitable and mutually acceptable
amendment to this Lease reflecting the same.

     29.9. If Tenant sublets the Premises or any portion thereof, Tenant hereby irrevocably authorizes Landlord, during the
continuance of a Default, to collect rent from any such subletting (and upon notice any subtenant shall pay directly to
Landlord) and apply the net amount collected toward Tenant’s obligations under this Lease.
  
                                                               47
30. Subordination and Attornment .
      30.1. Tenant agrees that this Lease and the rights of Tenant hereunder will be subject and subordinate to any lien of the
holder of any present or future mortgage, and to the rights of any lessor under any ground or improvements lease of the
Building (all mortgages and ground or improvements leases of any priority are collectively referred to in this Lease as
“Mortgage,” and the holder or lessor thereof from time to time as a “ Mortgagee ”), and to all advances and interest thereunder
and all modifications, renewals, extensions and consolidations thereof; provided that any subordination of this Lease shall be
conditioned upon Landlord delivering to Tenant a written, recordable subordination, non-disturbance and attornment
agreement (“ SNDA ”) from the Mortgagee seeking to have this Lease subordinated to its interest substantially in the form
attached as Exhibit J (or in such other commercially reasonable form as may be reasonably acceptable to the parties to such
agreement). Landlord represents and warrants that the only mortgage to which this Lease is subject as of the execution date is
that certain mortgage to Wells Fargo Bank, NA (the “ Existing Mortgagee ”). Landlord shall provide to Tenant, within 30 days
after the date of this Lease, an executed SNDA from the Existing Mortgagee.

      30.2. Notwithstanding the foregoing, Tenant shall execute and deliver upon demand such further reasonable instrument or
instruments as may be reasonably acceptable to the parties to such agreement evidencing such subordination of this Lease to
the lien of any such mortgage or mortgages or lease in which Landlord is tenant as may be reasonably required by Landlord. If
any such Mortgagee so elects, however, this Lease shall be deemed prior in lien to any such lease or mortgage upon or
including the Premises regardless of date and Tenant shall execute a statement in writing to such effect at Landlord’s request.
Tenant’s failure to execute any document required from Tenant under this Section within ten (10) business days after written 
request therefor, if such failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which 
notice shall state, in bold and prominent print, that failure to reply shall result in a Default under this Section 20.2), shall be a 
Default for which this Lease may be terminated without further notice.

      30.3. In the event any proceedings are brought for foreclosure, or in the event of the exercise of the power of sale under
any mortgage or deed of trust made by Landlord covering the Premises, Tenant shall at the election of the purchaser at such
foreclosure or sale attorn to the purchaser upon any such foreclosure or sale and recognize such purchaser as Landlord under
this Lease, so long as such purchaser recognizes Tenant as the tenant under this Lease and all of its rights hereunder, including
this Article.

     30.4. If from time to time Landlord assigns this Lease or the rents payable hereunder to any Mortgagee, whether such
assignment is conditional in nature or otherwise, such assignment shall not be deemed an assumption by the assignee of any
obligations of Landlord; the assignee shall be responsible only for non-performance of Landlord’s obligations that occur after it
succeeds to, and only during the period it holds possession of, Landlord’s interest in the Premises after foreclosure or
voluntary deed in lieu of foreclosure.
  
                                                                  48


31. Defaults and Remedies .
      31.1. Late payment by Tenant to Landlord of Rent and other sums due shall cause Landlord to incur costs not
contemplated by this Lease, the exact amount of which shall be extremely difficult and impracticable to ascertain. Such costs
include processing and accounting charges and late charges that may be imposed on Landlord by the terms of any mortgage or
trust deed covering the Premises. Therefore, if any installment of Rent due from Tenant is not received by Landlord within five
(5) business days after the date such payment is due, Tenant shall pay to Landlord (a) an additional sum of six percent (6%) of 
the overdue Rent as a late charge (provided that, with respect to the first late payment in any twelve (12) month period, no such 
late charge shall be due), plus (b) interest at an annual rate (the “ Default Rate ”) equal to the lesser of (a) twelve percent 
(12%) and (b) the highest rate permitted by Applicable Laws. The parties agree that this late charge represents a fair and 
reasonable estimate of the costs that Landlord shall incur by reason of late payment by Tenant and shall be payable as
Additional Rent to Landlord due with the next installment of Rent or within five (5) business days after Landlord’s demand,
whichever is earlier. Landlord’s acceptance of any Additional Rent (including a late charge or any other amount hereunder)
shall not be deemed an extension of the date that Rent is due or prevent Landlord from pursuing any other rights or remedies
under this Lease, at law or in equity.

    31.2. No payment by Tenant or receipt by Landlord of a lesser amount than the Rent payment herein stipulated shall be
deemed to be other than on account of the Rent, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as Rent be deemed an accord and satisfaction, and Landlord may accept such check or
payment without prejudice to Landlord’s right to recover the balance of such Rent or pursue any other remedy provided in this
Lease or in equity or at law. If a dispute shall arise as to any amount or sum of money to be paid by Tenant to Landlord
Lease or in equity or at law. If a dispute shall arise as to any amount or sum of money to be paid by Tenant to Landlord
hereunder, Tenant shall have the right to make payment “under protest,” such payment shall not be regarded as a voluntary
payment, and there shall survive the right on the part of Tenant to institute suit for recovery of the payment paid under protest.

      31.3. If Tenant fails to pay any sum of money required to be paid by it hereunder, or shall fail to perform any other act on
its part to be performed hereunder, in each case within the applicable notice and cure period (if any) described in Section 31.4 ,
then Landlord may, without waiving or releasing Tenant from any obligations of Tenant, but shall not be obligated to, make
such payment or perform such act; provided that such failure by Tenant unreasonably interfered with the use of the Building or
the Property by any other tenant or with the efficient operation of the Building or the Property, or resulted or could have
resulted in a violation of Applicable Laws or the cancellation of an insurance policy maintained by Landlord. Notwithstanding
resulted in a violation of Applicable Laws or the cancellation of an insurance policy maintained by Landlord. Notwithstanding
the foregoing, in the event of an emergency, Landlord shall have the right to enter the Premises upon such notice as is
reasonable under the circumstances, and act in accordance with its rights as provided elsewhere in this Lease. In addition to the
late charge described in Section 31.1 , Tenant shall pay to Landlord as Additional Rent all sums so paid or incurred by Landlord,
together with interest at the Default Rate, computed from the date such sums were paid or incurred.

     31.4. The occurrence of any one or more of the following events shall constitute a “ Default ” hereunder by Tenant:

          (a) Tenant abandons the Premises;
  
                                                                  49


           (b) Tenant fails to make any payment of Rent, as and when due, or to satisfy its obligations under Article 19 , where
such failure shall continue for a period of five (5) Business Days after written notice thereof from Landlord to Tenant; 

          (c) Tenant fails to observe or perform any obligation or covenant contained herein (other than described in
Subsections 31.4(a) and 31.4(b) ) to be performed by Tenant, where such failure continues for a period of thirty (30) days after 
written notice thereof from Landlord to Tenant; provided that, if the nature of Tenant’s default is such that it reasonably
requires more than thirty (30) days to cure, Tenant shall not be deemed to be in Default if Tenant commences such cure within 
such period and thereafter diligently prosecute the same to completion;

          (d) Tenant makes an assignment for the benefit of creditors;

          (e) A receiver, trustee or custodian is appointed to or does take title, possession or control of all or substantially all of
Tenant’s assets and is not removed within 60 days;

          (f) Tenant files a voluntary petition under the United States Bankruptcy Code or any successor statute (as the same
may be amended from time to time, the “ Bankruptcy Code ”) or an order for relief is entered against Tenant pursuant to a
voluntary or involuntary proceeding commenced under any chapter of the Bankruptcy Code;

           (g) Any involuntary petition is filed against Tenant under any chapter of the Bankruptcy Code and is not dismissed
within sixty (60) days; 

          (h) Tenant fails to deliver an estoppel certificate in accordance with Article 20 ; or

          (i) Tenant’s interest in this Lease is attached, executed upon or otherwise judicially seized and such action is not
released within sixty (60) days of the action. 

                 Notices given under this Section shall specify the alleged default and shall demand that Tenant perform the
provisions of this Lease or pay the Rent that is in arrears, as the case may be, within the applicable period of time, or quit the
Premises. No such notice shall be deemed a forfeiture or a termination of this Lease unless Landlord elects otherwise in such
notice.

    31.5. In the event of a Default by Tenant, and at any time thereafter, with or without notice or demand and without limiting
Landlord in the exercise of any right or remedy that Landlord may have, Landlord has the right to do any or all of the following:

           (a) Halt any Alterations and order Tenant’s contractors, subcontractors, consultants, designers and material
suppliers to stop work;

         (b) Terminate Tenant’s right to possession of the Premises by written notice to Tenant or by any lawful means, in
which case Tenant shall immediately surrender possession of the Premises to Landlord. In such event, Landlord shall have the
                                                BMR-650 E KENDALL B LLC,
immediate right to peaceably
                                             a Delaware limited liability company

                                                                 and
                                             AVEO PHARMACEUTICALS, INC.,
                                                 a Delaware corporation


                                                 TABLE OF CONTENTS
  
                                                                               Page  

1.        Lease of Premises                                                        1  
2.        Basic Lease Provisions                                                   2  
3.        Term                                                                     5  
4.        Possession and Commencement Date                                         5  
5.        Condition of Premises                                                    7  
6.        Rentable Area                                                            7  
7.        Rent                                                                     7  
8.        Rent Adjustments                                                         8  
9.        Operating Expenses                                                       8  
10.    Taxes on Tenant’s Property                                                  13  
11.    Security Deposit                                                            14  
12.    Use                                                                         15  
13.    Rules and Regulations, CC&Rs, Parking Facilities and Common Areas           18  
14.    Property Control by Landlord                                                21  
15.    Quiet Enjoyment                                                             22  
16.    Utilities and Services                                                      22  
17.    Alterations                                                                 25  
18.    Repairs and Maintenance                                                     28  
19.    Liens                                                                       30  
20.    Estoppel Certificate                                                        31  
21.    Hazardous Materials                                                         32  
22.    Odors and Exhaust                                                           35  
23.    Insurance; Waiver of Subrogation                                            36  
24.    Damage or Destruction                                                       38  
25.    Eminent Domain                                                              41  
26.    Surrender                                                                   42  
27.    Holding Over                                                                42  
28.    Indemnification and Exculpation                                             43  
29.    Assignment or Subletting                                                    44  
30.    Subordination and Attornment                                                48  
31.    Defaults and Remedies                                                       49  
31.    Defaults and Remedies                                                  49  
  
                                                i


                                       TABLE OF CONTENTS
                                           (continued)
  
                                                                          Page  

32.    Bankruptcy                                                             53  
33.    Brokers                                                                54  
34.    Definition of Landlord                                                 54  
35.    Limitation of Liability                                                55  
36.    Joint and Several Obligations                                          56  
37.    Representations                                                        56  
38.    Confidentiality                                                        57  
39.    Notices                                                                57  
40.    Rooftop Installation Area                                              57  
41.    Miscellaneous                                                          59  
42.    Options to Extend Term                                                 61  
43.    Right of First Offer                                                   62  
44.    Right of First Refusal                                                 64  
  
                                                ii


                                       TABLE OF DEFINITIONS
  
                                                                            Page  

Accountant                                                                   12  
ADA                                                                          17  
Additional Rent                                                               7  
Affected Areas                                                               38  
Alterations                                                                  25  
ANSI                                                                         42  
Applicable Laws                                                  3, 5, 8, 9, 10  
Available ROFO Premises                                                      63  
Available ROFR Premises                                                      64  
Bankruptcy Code                                                              50  
Base Rent                                                                     3  
Baseball Arbitrator                                                          61  
BMBL                                                                         33  
Broker                                                                       54  
Building                                                                      1  
CC&R                                                                         18  
Claims                                                                       17  
Common Area                                                                   1  
Cosmetic Alterations                                                         26  
Damage Repair Estimate                                                       39  
Damage Repair Estimate                                               39  
Default                                                              49  
Default Rate                                                         49  
DHHS                                                                 33  
Discount Rate                                                        51  
Execution Date                                                        1  
Exempt Transfers                                                     44  
Existing Mortgagee                                                   48  
Exit Survey                                                          42  
FMV                                                                  61  
Garage                                                               20  
Garage Operator                                                      20  
Garage Parking Spaces                                                20  
Generator                                                            24  
Governmental Authority                                                8  
Hazardous Material                                                   32  
Hazardous Materials Documents                                        33  
HVAC                                                                  5  
Independent Review                                                   11  
L/C Security                                                         14  
Land                                                                  1  
Landlord                                                          1, 54  
Landlord Delay                                                        6  
Landlord Indemnitees                                                 17  
Landlord Parties                                                     37  
  
                                         iii


                                TABLE OF DEFINITIONS
                                     (continued)
  
                                                                  Page  

Lease                                                                  1  
Lender                                                                17  
Mortgagee                                                             48  
MWRA                                                                  18  
New Tenant                                                            35  
New Tenant                                         35  
Notice of Marketing                                63  
Notice of Offer                                    64  
OFAC                                               56  
Operating Expenses                                  8  
Option                                             61  
Option Notice                                      61  
Phase 1 Premises                                    5  
Phase 1 Premises Deadline                           5  
Phase 1 Premises Rent Commencement Date             5  
Phase 1 Premises Tenant Improvements                5  
Phase 2 Premises                                    5  
Phase 2 Premises Rent Commencement Date             5  
Phase 2 Premises Tenant Improvements                5  
Phase 2 Premises Tenant Improvements             5  
Premises                                         1  
Property                                         1  
Property Management Fee                         11  
Property Operations Agreements                  18  
REBA                                            61  
REFA                                            61  
Revenue Code                                    45  
ROFO                                            63  
ROFR                                            64  
Rooftop Installation Area                       57  
Rules and Regulations                           18  
Security Deposit                                14  
Signage                                         16  
SNDA                                            48  
Specialty Alterations                           27  
Substantial Completion                           6  
Substantially Complete                           6  
Tenant                                           1  
Tenant Improvements                              6  
Tenant Premises Notice                           2  
Tenant Premises Notice                                                                                                         2  
Tenant’s Affiliate                                                                                                            44  
Tenant’s Parking Spaces                                                                                                       19  
Tenant’s Rooftop Equipment                                                                                                    58  
Tenant’s Share                                                                                                                10  
Term                                                                                                                           5  
Term Expiration Date                                                                                                           5  
Termination Notice                                                                                                            39  
  
                                                              iv


                                                 TABLE OF DEFINITIONS
                                                      (continued)
  
                                                                                                                          Page  

TI Allowance                                                                                                                   6  
TI Deadline                                                                                                                    6  
Transfer                                                                                                                      44  
Transfer Date                                                                                                                 44  
Transfer Notice                                                                                                               44  
UBC                                                                                                                           34  
Work Letter                                                                                                                    6  
  
                                                              v


                                                           LEASE

     THIS LEASE (this “ Lease ”) is entered into as of this 9th day of May, 2012 (the “ Execution Date ”), by and between BMR-
650 E Kendall B LLC, a Delaware limited liability company (“ Landlord ”), and AVEO Pharmaceuticals, Inc., a Delaware
corporation (“ Tenant ”).

                                                              RECITALS

     A. WHEREAS, Landlord owns certain real property commonly known as Parcel B and described further on Exhibit A-1
attached hereto (the “ Land ”) and the improvements on the Property located at 650 East Kendall Street, Cambridge,
Massachusetts, including the building and the Garage (as defined in Section 13.5) (collectively, the “Building”) in which the
Premises (as defined below) are located; and

     B. WHEREAS, Landlord wishes to lease to Tenant, and Tenant desires to lease from Landlord, certain premises (the “ 
Premises ”) located on a portion of the fourth (4th) floor, and the entire fifth (5th) and sixth (6th) floors, together with certain off-
floor mechanical areas, of the Building, pursuant to the terms and conditions of this Lease, as detailed below.


                                                            AGREEMENT

     NOW, THEREFORE, Landlord and Tenant, in consideration of the mutual promises contained herein and for other good
and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and intending to be legally bound,
agree as follows:

1. Lease of Premises .
      1.1. Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord, the Premises, as shown on Exhibit A
attached hereto for use by Tenant in accordance with the Permitted Use (as defined below) and no other uses. The Building,
Land and all landscaping, parking facilities, private drives and other improvements and appurtenances located thereon and
related thereto, including the Building and other buildings located on the Land, are hereinafter collectively referred to as the “ 
Property .” All portions of the Building and Property that are for the non-exclusive use of the tenants of the Property, such as
service corridors, elevators, loading docks, public restrooms, public entranceways, lobbies and stairways, electric and
telephone closets (other than those exclusively serving the Premises, if any), janitor closets, and other areas from time to time
designated as common areas by Landlord (all to the extent located in the Building or on the Property) are hereinafter referred to
as “ Common Area .” The Premises exclude Common Areas, fan rooms, mechanical rooms, elevators wells, pipes, ducts,
conduits, wires and appurtenant fixtures serving other parts of the Property (exclusively or in common), and any exterior walls
(including without limitation the roof and roof system) and structural members of the Building. If the Premises include less than
the entire rentable area of any floor, then the Premises also exclude the common corridors, elevator lobby and toilets located on
such floor.


      Tenant shall have the right, on or before to June 1, 2012, in each case by written notice (a “ Tenant Premises Notice ”) to
Landlord identifying the alternative demising of the Premises proposed by Tenant, to (x) reduce or expand the portion of the 
Premises located on the fourth floor by adjusting the location of the demising walls between the Premises and contiguous
leaseable areas on the fourth floor by an amount not to exceed five thousand (5,000) square feet of Rentable Area, provided that 
the remainder of the leaseable areas on the fourth floor are readily leaseable for multi-tenant purposes in a first class office and
laboratory building, as reasonably determined by Landlord; there is no adverse impact on Building systems or structure as a
result of such adjustment; and/or (y) substitute alternative, existing off-floor mechanical locations in the Building for the off-
floor mechanical portions of the Premises, provided that such areas are, in Landlord’s reasonable determination, of an
equivalent aggregate Rentable Area, do not impose an inequitable allocation or use of similar mechanical spaces for tenant
spaces in the Building, do not reduce any leaseable areas of the Building, and do not adversely affect Building operations or
access. Within 10 days following the giving of a Tenant Premises Notice, Landlord shall approve the proposed revised Premises
or disapprove such proposal with specific reasons therefor. Landlord’s failure to respond within such ten day period shall be
deemed approval by Landlord. Following the adjustment of the Premises in accordance with this Section, the parties shall enter
into an amendment to this Lease substituting the revised Premises plans for the applicable floors of the Premises for the
Premises plans initially attached as Exhibit A hereto, and the annual Base Rent, Tenant’s Parking Spaces, and Tenant’s Pro Rata
Share (as each term is defined below) shall be adjusted accordingly based on the change in Rentable Area of the Premises as
determined by Landlord in accordance with Article 6, below.

2. Basic Lease Provisions . For convenience of the parties, certain basic provisions of this Lease are set forth herein. The
provisions set forth herein are subject to the remaining terms and conditions of this Lease and are to be interpreted in light of
such remaining terms and conditions.

     2.1. This Lease shall take effect upon the Execution Date and, except as specifically otherwise provided within this Lease,
each of the provisions hereof shall be binding upon and inure to the benefit of Landlord and Tenant from the date of execution
and delivery hereof by all parties hereto.

    2.2. In the definitions below, each current Rentable Area (as defined below) is expressed in rentable square footage.
Rentable Areas and “ Tenant’s Pro Rata Shares ” are all subject to adjustment only as expressly provided in this Lease.
Rentable Areas and “ Tenant’s Pro Rata Shares ” are all subject to adjustment only as expressly provided in this Lease.
  
                                                                                      Means the Following (As of the
                        Definition or Provision                                             Execution Date)
                        Rentable Area of Premises                                           126,065 square feet
                        Rentable Area of Building                                           291,498 square feet
                        Rentable Area of Lab Building                                       278,736 square feet
                        Tenant’s Pro Rata Share of Building                                      43.25%
                        Tenant’s Pro Rata Share of Lab Building                                  45.23%
  
                                                                        2


   2.3. Initial monthly and annual installments of Base Rent for the Premises (“ Base Rent ”) as of the Phase 1 Premises Rent
Commencement Date (as defined in Section 4.1 below), subject to adjustment under this Lease:
  
                                                                                              Base Rent per 
                                                                  Square Feet of              Square Foot of 
                                                                  Rentable Area              Rentable Area of      Monthly Base          Annual Base
Dates                                                            for the Premises              the Premises           Rent                  Rent       
Phase 1 Premises Rent Commencement Date – the date                            126,065       $54.50 annually          $572,545.21        $6,870,542.50  
  immediately preceding the first (1 st ) anniversary of
  the Phase 1 Premises Rent Commencement Date                                                                                        

     As further described in Section 4.1, below, Base Rent shall be prorated for the Premises between the Phase 1 and Phase 2 
Premises, and only payable with respect to the Phase 1 Premises, until such time as the Phase 2 Premises Rent Commencement
Date occurs.

     2.4. Term Commencement Date: The date upon which Landlord delivers the Premises to Tenant in its “as is” condition as
of the date hereof with a temporary demising wall constructed on the 4th floor of the Building that is reasonably sufficient for
Tenant to secure such portion of the Premises, which date Landlord shall cause to occur no later than May 31, 2012. 

        2.5. Estimated Term Expiration Date: December 31, 2024. 

        2.6. Security Deposit: $2,862,726.

     2.7. Permitted Use: Office and laboratory use in conformity with all federal, state, municipal and local laws, codes,
ordinances, rules and regulations of Governmental Authorities (as defined below), committees, associations, or other regulatory
committees, agencies or governing bodies having jurisdiction over the Premises, the Building, the Property, Landlord or Tenant,
including both statutory and common law and hazardous waste rules and regulations (“ Applicable Laws ”). Tenant shall obtain
validation by any medical review board or other similar governmental licensing of the Premises required for the Permitted Use.
  
                                                                        3


                     2.8. Address for Rent Payment:                      BMR-650 E Kendall B LLC

                                                                         Pursuant   to the following wire instructions:
                                                                         Name of beneficiary: BMR-650 E Kendall B LLC
                                                                         Account number: 153495105154
                                                                         Bank Name: US Bank
                                                                         Routing/Transit #: 122235821
                                                                         Branch Name & Address: San Diego Main
                                                                         600 W Broadway #100
                                                                         San Diego, CA 92101

                     2.9. Address for Notices to Landlord:               BMR-650 E Kendall B LLC

                                                                         17190 Bernardo Center Drive
                                                                         San Diego, California 92128
                                                                         Attn: Vice President, Real Estate       Counsel
2.10. Address for Notices to Tenant:     

Prior to the Rent Commencement Date:     AVEO Pharmaceuticals, Inc.
                                         75 Sidney Street
                                         Cambridge, MA 02139
                                         Attn: Chief Financial Officer
                 On or after the Rent Commencement Date:      At the Premises
                 With a copy to:                                Langer & McLaughlin,   LLP
                                                                855 Boylston Street
                                                                Boston, MA 02116


                 2.11. The following Exhibits are attached hereto and incorporated herein by reference:
  
                         Exhibit A        Premises
                         Exhibit A-1      Land
                         Exhibit B        Work Letter
                         Exhibit B-1       Scope of Landlord’s Demising Work
                         Exhibit C        Acknowledgement of Rent Commencement    Date and Term Expiration Date
                         Exhibit D        Development Approvals
                         Exhibit E        Form of Letter of Credit
                         Exhibit F        Rules and Regulations
                         Exhibit G        Tenant’s Personal Property
                         Exhibit H        Form of Estoppel Certificate
                         Exhibit I        SNDA
                         Exhibit J        Rooftop Installation Area
                         Exhibit K        Kendall Square
                         Exhibit L        Tenant’s Signage Location
  
                                                                4


3. Term . The actual term of this Lease (as the same may be extended pursuant to Article 42 hereof, and as the same may be
earlier terminated in accordance with this Lease, the “ Term ”) shall commence on the Term Commencement Date and end on the
date that is twelve (12) years after the actual Phase 1 Premises Rent Commencement Date (such date, the “ Term Expiration Date
”), subject to earlier termination of this Lease as provided herein, provided that if the Phase 1 Premises Rent Commencement
Date is not the first day of a calendar month, then the Term Expiration Date shall be the last day of the calendar month in which
the twelfth (12 th ) anniversary of the Phase 1 Premises Rent Commencement Date occurs. 
4. Possession and Commencement Date .
      4.1. Landlord has delivered to Tenant, broom clean and free of occupants, and Tenant has accepted possession of, the
Premises as of the date hereof. Landlord represents and warrants to Tenant that, as of the date hereof, the heating, ventilation
and air-conditioning (“HVAC”), electrical, life safety and plumbing systems of the Building are in good working condition and,
to the best of Landlord’s knowledge, not in violation of Applicable Laws applicable to office and laboratory use, generally.
Tenant shall undertake its Tenant Improvements and occupy the Premises for the conduct of its business in two phases. The “ 
Phase 1 Premises ” shall consist of not less than twenty thousand (20,000) square feet of Rentable Area on the sixth (6th) floor 
of the Building identified by Tenant to Landlord no later than June 1, 2012 (the “ Phase 1 Premises Deadline ”). If Tenant fails to
provide Landlord with such notice by the Phase 1 Premises Deadline, then the Phase 1 Premises shall be as shown on Exhibit B-
2 attached hereto. Promptly following the Phase 1 Premises Deadline, the parties shall enter into a written instrument confirming
the square footage of Rentable Area of the Phase 1 Premises. The “ Phase 2 Premises ” shall consist of the balance of the
Premises. The Rent Commencement Date shall be determined separately for each Phase and Base Rent shall be prorated based
on the ratio of square footage of the Phase 1 Premises to the entire Premises until such time as the “Rent Commencement Date” 
occurs with respect to the entire Premises (i.e., until such time as the Phase 2 Premises Rent Commencement Date occurs). The “ 
Phase 1 Premises Rent Commencement Date ” shall be the earlier of (a) the Date earlier to occur of (i) Substantial Completion of 
the work described on Exhibit B with respect to the Phase 1 Premises (the “ Phase 1 Premises Tenant Improvements ”), and
(ii) January 1, 2013 and (b) the date on which Tenant has occupied any portion of the Phase 1 Premises for the conduct of its 
business, as opposed to occupying any portion of the Phase 1 Premises for the installation of the Tenant Improvements (as
defined below). The “ Phase 2 Premises Rent Commencement Date ” shall be the earlier of (y) the Date that is the earlier to occur 
of (i) Substantial Completion of the work described on Exhibit B with respect to the Phase 2 Premises (the “ Phase 2 Premises
Tenant Improvements ” and, together with the Phase 1 Premises Tenant Improvements, the
  
                                                                5


“ Tenant Improvements ”), and (ii) November 1, 2013 and (z) the date on which Tenant has occupied any portion of the Phase 2 
“ Tenant Improvements ”), and (ii) November 1, 2013 and (z) the date on which Tenant has occupied any portion of the Phase 2 
Premises for the conduct of its business, as opposed to occupying any portion of the Phase 2 Premises for the installation of
the Tenant Improvements. Each of the Phase 1 Premises Rent Commencement Date and the Phase 2 Premises Rent
Commencement Date shall be subject to extension for Landlord Delay as further described in Section 4 of Exhibit B hereto. Each
party shall execute and deliver to the other written acknowledgment of the actual Commencement Date, the actual Phase 1
Premises Rent Commencement Date, the actual Phase 2 Premises Rent Commencement Date and/or the Term Expiration Date
within ten (10) business days after request by the other party, substantially in the form attached as Exhibit C hereto. Failure to
execute and deliver such acknowledgment, however, shall not affect the Phase 1 Premises Rent Commencement Date, the Phase
2 Premises Rent Commencement Date, the Term Expiration Date or Landlord’s or Tenant’s liability hereunder. The term “ 
Substantially Complete ” or “ Substantial Completion ” means that the applicable Phase of Tenant Improvements is
substantially complete in accordance with the Approved Plans (as defined in Exhibit B hereto), except for minor punch list items,
and that Tenant is able to lawfully occupy the Premises for the conduct of its business in accordance with the Permitted Use.

      4.2. Tenant shall cause the Tenant Improvements to be constructed in the Premises pursuant to the Work Letter attached
hereto as Exhibit B (the “ Work Letter ”) at a cost to Landlord not to exceed Eighteen Million Nine Hundred Nine Thousand
Seven Hundred Fifty and 00/100 Dollars ($18,909,750.00) (based upon One Hundred Fifty and 00/100 Dollars ($150.00) per
square foot of Rentable Area (as defined below)) (the “ TI Allowance ”). The TI Allowance may be applied to the costs of
(s) construction, (t) building permits and other permits, approvals, taxes, fees, charges and levies by Governmental Authorities 
(as defined below) for permits or for inspections of the Tenant Improvements, and (u) costs and expenses for labor, material, 
equipment and fixtures. In no event shall the TI Allowance be used for (v) the cost of work that is not authorized by the 
Approved Plans (as defined in the Work Letter) or otherwise approved in writing by Landlord, (w) payments to Tenant or any 
affiliates of Tenant, (x) Tenant’s soft costs or the purchase of any furniture, personal property or other non-building system
equipment, (y) costs resulting from any default by Tenant of its obligations under this Lease or (z) costs to extent recoverable 
by Tenant from a third party (e.g., insurers, warrantors, or tortfeasors). Notwithstanding the foregoing to the contrary, Tenant
may apply up to ten percent (10%) of the TI Allowance toward the costs of Tenant’s architectural, engineering, and project
management fees, data/telecom cabling, relocation expenses, and an additional amount up to ten percent (10%) of the TI 
Allowance towards the costs of Tenant’s furniture, fixtures and equipment installation related to the initial occupancy of the
Premises. In no event shall any unused TI Allowance entitle Tenant to a credit against Rent payable under this Lease. Tenant
shall have until May 31, 2014 (the “ TI Deadline ”) to requisition the unused portion of the TI Allowance, after which date
Landlord’s obligation to fund such costs shall expire.

     4.3. The Phase 1 Premises and Phase 2 Premises are sometimes generically referred to herein as a “Phase”.
  
                                                                6


     4.4. Prior to entering upon the Premises, Tenant shall furnish to Landlord evidence satisfactory to Landlord that insurance
coverages required of Tenant under the provisions of Article 23 are in effect.

5. Condition of Premises . Tenant acknowledges that neither Landlord nor any agent of Landlord has made any
representation or warranty with respect to the condition of the Premises, the Building or the Property, or with respect to
the suitability of the Premises, the Building or the Property for the conduct of Tenant’s business, except as expressly set
forth in this Lease. Without in any way derogating from Landlord’s ongoing maintenance, repair and restoration
obligations set forth elsewhere in this Lease, Tenant acknowledges that (a) it is familiar with the condition of the Premises 
and agrees to take the same in its condition “as is” as of the Execution Date and (b) Landlord shall have no obligation to 
alter, repair or otherwise prepare the Premises for Tenant’s occupancy or to pay for or construct any improvements to the
Premises, except with respect to the TI Allowance; provided, however, that Landlord shall separately demise that portion
of the Premises located on the fourth (4th) floor of the Building separately as shown on Exhibit B-1 attached hereto and
furnish and provide a reception desk in the main building lobby as further provided in Exhibit B , at Landlord’s sole cost
and expense (in addition to the TI Allowance).

6. Rentable Area . The Rentable Areas initially set forth herein are deemed conclusive between the parties and are not subject to
remeasurement, except that in the event that the size of the Premises or Building is actually reduced or expanded pursuant to the
provisions of Articles 1, 24, 25, 43 or 44 below, the Rentable Areas (and, as applicable, Tenant’s Pro Rata Share) shall be
adjusted as reasonably calculated by Landlord’s architect in a manner consistent with Landlord’s initial determination of
Rentable Areas for the Premises and the Building.

7. Rent .
     7.1. Tenant shall pay to Landlord as Base Rent for the Premises, commencing on the Phase 1 Premises Rent
Commencement Date, the sums set forth in Section 2.3 , subject to the rental adjustments provided in Section 4.1 and Article 8
hereof. Base Rent shall be paid in equal monthly installments, subject to the rental adjustments provided in Section 4.1 and
Article 8 hereof, each in advance on the first day of each and every calendar month during the Term.

      7.2. In addition to Base Rent, Tenant shall pay to Landlord as additional rent (“ Additional Rent ”) at times hereinafter
specified in this Lease (a) Tenant’s Share (as defined below) of Operating Expenses (as defined below), (b) the Property 
Management Fee (as defined below) and (c) any other amounts that Tenant assumes or agrees to pay under the provisions of 
this Lease that are owed to Landlord, including any and all other sums that may become due by reason of any default of Tenant
or failure on Tenant’s part to comply with the agreements, terms, covenants and conditions of this Lease to be performed by
Tenant, after notice and the lapse of any applicable cure periods.

     7.3. Base Rent and Additional Rent shall together be denominated “Rent.” Rent shall be paid to Landlord in lawful money
of the United States of America at the office of Landlord as set forth in Section 2.8 or to such other person or at such other 
place as Landlord may from time designate in writing. In the event the Phase 1 Rent Commencement Date or Phase 2 Rent
  
  
                                                                 7


Commencement Date occurs or the Term ends on a day other than the first day of a calendar month, then the Rent for such
fraction of a month shall be prorated for such period on the basis of a thirty (30) day month and shall be paid at the then-current
rate for such fractional month. All payments of Rent shall be made without set-off, deduction or offset except as expressly
provided in this Lease. Without limiting the foregoing, Tenant’s obligation to pay Rent shall be absolute, unconditional, and
independent and shall not be discharged or otherwise affected by any Applicable Laws now or hereafter applicable to the
Premises, or any other restriction on Tenant’s use, or, except as provided in Articles 24 and 25 , any casualty or taking, or any
failure by Landlord to perform or other occurrence; and Tenant assumes the risk of the foregoing and waives all rights now or
hereafter existing to quit or surrender the Premises or any part thereof, to terminate or cancel this Lease, or to assert any defense
in the nature of constructive eviction in any action seeking to recover rent (other than mandatory counterclaims). Subject to the
provisions of this Lease, however, Tenant shall have the right to injunctive relieve or to seek judgments for direct money
damages occasioned by Landlord’s breach of its Lease covenants (but may not set-off any such judgment against any rent or
other amount owing hereunder). Nothing in this Section 7.3 shall limit the exercise of Tenant’s express remedies on the terms
and conditions set forth in Sections 16.2 and  18.3 below).

8. Rent Adjustments . Base Rent shall be subject to an annual upward adjustment of three percent (3%) of the then-current Base
Rent during the initial Term. The first such adjustment shall become effective commencing on the first (1 st ) annual anniversary 
of the Phase 1 Premises Rent Commencement Date, and subsequent adjustments shall become effective on every successive
annual anniversary for the remainder of the initial Term of this Lease.

9. Operating Expenses .
     9.1. As used herein, the term “ Operating Expenses ” shall include:

           (a) Government impositions, including property tax costs consisting of real and personal property taxes and
assessments (including amounts due under any improvement bond upon the Building or the Property (including the parcel or
parcels of real property upon which the Building, the other buildings on the Property and areas serving the Building and the
Property are located)) or assessments in lieu thereof imposed by any federal, state, regional, local or municipal governmental
authority, agency or subdivision (each, a “ Governmental Authority ”); taxes on or measured by gross rentals received from the
rental of space in the Property; taxes based on the square footage of the Premises, the Building or the Property, as well as any
parking charges, utilities surcharges or any other costs levied, assessed or imposed by, or at the direction of, or resulting from
Applicable Laws or interpretations thereof, promulgated by any Governmental Authority in connection with the use or
occupancy of the Building or Property or the parking facilities serving the Building; any actual and reasonable third party
expenses, including the reasonable cost of attorneys or experts, reasonably incurred by Landlord in seeking reduction by the
taxing authority of the applicable taxes. If Landlord is successful in obtaining any refund, abatement or other reduction of any
taxes payable in respect of the Property for any year for which Tenant has paid Operating Expenses, Landlord shall promptly
refund to Tenant Tenant’s Pro Rata Share of the Building of such refund, abatement or other reduction (including any interest
refund to Tenant Tenant’s Pro Rata Share of the Building of such refund, abatement or other reduction (including any interest
paid by the taxing authority),
  
                                                                  8


but in any event not to exceed amounts actually paid by Tenant on account of such taxes during such period. To the extent that
Landlord is billed for any taxes on the execution of this Lease or any other document to which Tenant is a party creating or
transferring an interest in the Premises, Tenant shall pay the same directly to Landlord within thirty (30) days after receipt of an 
invoice therefor (which invoice shall be accompanied by a copy of the applicable tax bill(s)). Operating Expenses shall not
include any state, federal or local net income, franchise, capital stock, estate, transfer or inheritance taxes, or taxes that are the
personal obligation of Tenant or of another tenant of the Property; and

           (b) All other actual third party costs (or costs for Landlord personnel or services provided by Landlord so long as the
same is provided at a cost that does not exceed the cost of such personnel or service rendered by unaffiliated third parties on a
competitive basis) of any kind paid or incurred by Landlord in connection with the operation or maintenance of the Building and
the Property, including costs of repairs and replacements to improvements within the Property as appropriate to maintain the
Property as required hereunder; costs of utilities furnished to the Common Areas; sewer fees; trash collection (including
recyclables, but excluding special handling or collection costs associated with collection of any Hazardous Materials not
customarily collected in the ordinary maintenance of a first class office and laboratory building); Common Area cleaning,
including windows; heating; ventilation; air-conditioning; maintenance of landscaping and grounds; maintenance of drives and
parking areas; maintenance of the roof; security services and devices; building supplies; maintenance or replacement of
equipment utilized for operation and maintenance of the Property; license, permit and inspection fees; sales, use and excise
taxes on goods and services purchased by Landlord in connection with the operation, maintenance or repair of the Building or
Property systems and equipment; telephone, postage, stationery supplies and other expenses incurred in connection with the
operation, maintenance or repair of the Property; accounting, legal and other professional fees and expenses incurred in
connection with the Property; costs of furniture, draperies, carpeting, landscaping, snow removal and other customary and
ordinary items of personal property provided by Landlord for use in Common Areas; Property office rent or rental value for a
commercially reasonable amount of space, to the extent an office used for Property operations is maintained at the Property,
plus customary expenses for such office; capital expenditures amortized over the useful life thereof, as reasonably determined
by Landlord, in accordance with generally accepted accounting principles ; costs of complying with Applicable Laws (except to
the extent such costs are incurred to remedy non-compliance as of the Execution Date with Applicable Laws); costs to keep the
Property in compliance with, or fees otherwise required under, any Property Operations Agreements (as defined below);
insurance premiums; portions of insured losses paid by Landlord as part of a deductible portion of a loss pursuant to the terms
of insurance policies (provided that such deductibles are commercially reasonable); service contracts; costs of services of
independent contractors retained to do work of a nature referenced above; and costs of compensation (including employment
taxes and fringe benefits) of all persons who perform regular and recurring duties connected with the day-to-day operation and
maintenance of the Property, its equipment, the adjacent walks, landscaped areas, drives and parking areas, including janitors,
floor waxers, window washers, watchmen, gardeners, sweepers, plow trucks and handymen. Operating Expenses for each year
will be calculated in a reasonably consistent manner.
  
                                                                  9
            (c) Notwithstanding the foregoing, Operating Expenses shall not include any (i) leasing commissions; (ii) expenses 
that relate to preparation of rental space for a tenant; (iii) expenses of initial development and construction of the Building, or of 
any expansion or elective upgrade (other than for the primary purpose of reducing Operating Expenses as described in clause
(x) below) of the Building or Common Areas, including grading, paving, landscaping and decorating (as distinguished from 
maintenance, repair and replacement of the foregoing); (iv) legal expenses relating to other tenants; (v) costs of repairs to the 
extent Landlord is entitled to be reimbursed by payment of insurance, warranties or guaranties or by any other third party or
parties; (vi) principal amount of, or interest upon loans to Landlord or secured by a mortgage or deed of trust covering the 
Property or a portion thereof; (vii) costs to operate, maintain, or repair the Garage; (viii) salaries of executive officers of 
Landlord; (ix) depreciation claimed by Landlord for tax purposes (other than amortization of capital expenditures as expressly 
provided herein); (x) capital improvements (as distinguished from repairs and maintenance) unless and except to the extent 
incurred (i) in replacing obsolete equipment or other capital items, (ii) for the primary purpose of reducing Operating Expenses or 
(iii) required by any Governmental Authority to comply with changes in Applicable Laws that take effect after the Execution 
Date or to ensure continued compliance with Applicable Laws in effect as of the Execution Date (but expressly excluding the
costs of curing or contesting violations of Applicable Law that existed on or prior to the Execution Date); (xi) the cost of 
leasehold improvements, including without limitation redecorating or renovation work, for other tenants in the Building; (xii) to 
the extent of any increase in Landlord’s insurance rates which may result from the grossly negligent failure of Landlord or its
agents, employees or contractors to comply with the provisions of this Lease; (xiii) the cost of any work or service performed 
for any tenant in the Building (other than Tenant) to a materially greater extent or in a materially more favorable manner than that
furnished generally to tenants (including Tenant) in the Building; (xiv) the general corporate overhead costs and expenses of 
the Landlord entity (except to the extent of the Property Management Fee and personnel costs at the level of Senior Property or
Facilities Manager and below to the extent related to the Property); (xv) costs and expenses incurred in any dispute with any 
particular tenant; (xvi) any costs of remediation of hazardous materials or substances in the Building, or on the land parcels on 
which it is located; (xvii) any costs (other than the Property Management Fee described below) representing an amount paid to 
an entity related to Landlord which is in excess of the amount which would have been paid absent such relationship; and
(xviii) taxes that are excluded from Operating Expenses by the last sentence of Subsection 9.1(a) . To the extent that Tenant uses
more than Tenant’s Pro Rata Share of the Building of any item of Operating Expenses, Landlord shall provide notice to Tenant
of such excess usage, and Tenant shall pay Landlord for such excess in addition to Tenant’s obligation to pay Tenant’s Pro
Rata Share of Lab Building of Operating Expenses for the Property (such excess, together with Tenant’s Pro Rata Share of Lab
Building, “ Tenant’s Share ”). Notwithstanding anything in this Article 9 to the contrary, Tenant’s Share with respect to taxes
and other impositions as set forth in Subsection 9.1(a) and to expenses payable by the Building under the CC&Rs shall mean
such excess together with Tenant’s Pro Rata Share of the Building. Nothing in this paragraph shall be deemed to limit the extent
to which CC&Rs are included in Operating Expenses.

    9.2. Tenant shall pay to Landlord on the first day of each calendar month of the Term, following the Phase 1 Premises Rent
Commencement Date, as Additional Rent, (a) the Property Management Fee (as defined below) and (b) Landlord’s estimate of
Tenant’s Share of Operating Expenses for such month.
  
                                                                  10


          (x) The “ Property Management Fee ” shall equal three percent (3%) of Base Rent due from Tenant. Tenant shall pay 
the Property Management Fee in accordance with Section 9.2 with respect to the entire Term, commencing on the applicable
Rent Commencement Date, including any extensions thereof or any holdover periods, regardless of whether Tenant is obligated
to pay Base Rent, Operating Expenses or any other Rent with respect to any such period or portion thereof, except as expressly
to pay Base Rent, Operating Expenses or any other Rent with respect to any such period or portion thereof, except as expressly
provided in this Lease.

           (y) Within ninety (90) days after the conclusion of each calendar year (or such longer period as may be reasonably 
required by Landlord but in any event not to exceed one year), Landlord shall furnish to Tenant a statement showing in
reasonable detail the actual Operating Expenses and Tenant’s Share of Operating Expenses for the previous calendar year. Any
additional sum due from Tenant to Landlord shall be due and payable within thirty (30) days. If the amounts paid by Tenant 
pursuant to this Section exceed Tenant’s Share of Operating Expenses for the previous calendar year, then Landlord shall credit
the difference against Tenant’s Share of Operating Expenses next due and owing from Tenant; provided that, if the Term has
expired, Landlord shall accompany such statement with payment for the amount of such difference.

          (z) Any amount due under this Section for any period that is less than a full month shall be prorated (based on a thirty
(30)-day month) for such fractional month.

      9.3. Landlord’s annual statement shall be final and binding upon Tenant unless Tenant, within 180 days after Tenant’s
receipt thereof, shall contest any item therein by giving written notice to Landlord, specifying in reasonable detail the reasons
therefor; provided that Tenant shall in all events pay the amount specified in Landlord’s annual statement, pending the results
of the Independent Review and determination of the Accountant(s), as applicable and as each such term is defined below. At
the request of Tenant at any time within such 180-day period, Landlord shall provide Tenant with reasonable access to
Landlord’s books and records to the extent relevant to determination of Operating Expenses, and such information as Landlord
reasonably determines to be responsive to Tenant’s written inquiries. In the event that, after Tenant’s review of such
information, Landlord and Tenant cannot agree upon the amount of Tenant’s Share of Operating Expenses, then Tenant shall
have the right to have a qualified and reputable third party consultant or accounting firm hired by Tenant (but not on a
contingent-fee basis) at Tenant’s sole cost and expense audit and review such of Landlord’s books and records for the year in
question as directly relate to the determination of Operating Expenses for such year (the “ Independent Review ”). Landlord
shall make such books and records available at the location where Landlord maintains them in the ordinary course of its
business, but need not provide Tenant with copies of any books or records. Tenant shall commence the Independent Review
within thirty (30) days after the date Landlord has given Tenant access to Landlord’s books and records for the Independent
Review and following at least 10 days’ prior notice to Landlord of the identity of the consultant or accounting firm conducting
such review so that Landlord can confirm that such reviewer meets the foregoing qualifications. Tenant shall complete the
Independent Review and notify Landlord in writing of
  
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Tenant’s specific objections to Landlord’s calculation of Operating Expenses (including Tenant’s accounting firm’s written
statement of the basis, nature and amount of each proposed adjustment) no later than sixty (60) days after Landlord has first 
given Tenant access to Landlord’s books and records for the Independent Review. Landlord shall review the results of any
such Independent Review. The parties shall endeavor to agree promptly and reasonably upon Operating Expenses taking into
account the results of such Independent Review. If, as of sixty (60) days after Tenant has submitted the Independent Review to 
Landlord, the parties have not agreed on the appropriate adjustments to Operating Expenses, then the parties shall engage a
mutually agreeable independent third party accountant with at least ten (10) years’ experience in commercial real estate
mutually agreeable independent third party accountant with at least ten (10) years’ experience in commercial real estate
accounting in the Kendall Square, Cambridge, Massachusetts area (the “ Accountant ”). If the parties cannot agree on the
Accountant, each shall within ten (10) days after such impasse appoint an Accountant (different from the accountant and 
accounting firm that conducted the Independent Review) and, within ten (10) days after the appointment of both such 
Accountants, those two Accountants shall select a third (which cannot be the accountant and accounting firm that conducted
the Independent Review). If either party fails to timely appoint an Accountant, then the Accountant the other party appoints
shall be the sole Accountant. Within ten (10) days after appointment of the Accountant(s), Landlord and Tenant shall each 
simultaneously give the Accountants (with a copy to the other party) its determination of Operating Expenses, with such
simultaneously give the Accountants (with a copy to the other party) its determination of Operating Expenses, with such
supporting data or information as each submitting party determines appropriate. Within ten (10) days after such submissions, 
the Accountants shall by majority vote select either Landlord’s or Tenant’s determination of Operating Expenses. The
Accountants may not select or designate any other determination of Operating Expenses. The determination of the Accountant
(s) shall bind the parties. If the parties agree or the Accountant(s) determine that the Operating Expenses actually paid by
Tenant for the calendar year in question exceeded Tenant’s obligations for such calendar year, then Landlord shall, at Tenant’s
option, either (a) credit the excess to the next succeeding installments of estimated Additional Rent or (b) pay the excess to 
Tenant within thirty (30) days after delivery of such results. If the parties agree or the Accountant(s) determine that Tenant’s
payments of Operating Expenses for such calendar year were less than Tenant’s obligation for the calendar year, then Tenant
shall pay the deficiency to Landlord within thirty (30) days after delivery of such results. If the Independent Review reveals or 
the Accountant(s) determine that the Operating Expenses billed to Tenant by Landlord and paid by Tenant to Landlord for the
applicable calendar year in question exceeded by more than four percent (4%) what Tenant should have been billed during such 
calendar year, then Landlord shall pay the reasonable cost of the Independent Review and the Accountants. In all other cases,
Tenant shall pay the cost of the Independent Review, and one-half of the cost of the Accountants. Any Operating Expense not
billed to Tenant on or before the second (2 nd ) anniversary of the last day of the calendar year in which such Operating Expense 
was billed to or incurred by Landlord shall be deemed waived by Landlord, and Tenant shall have no liability or obligation with
respect thereto.

     9.4. Tenant shall not be responsible for Operating Expenses attributable to the time period prior to the Phase 1 Premises
Rent Commencement Date, with respect to the Phase 1 Premises; or the Phase 2 Premises Rent Commencement Date, with
respect to the Phase 2 Premises.
     9.5. Operating Expenses for the calendar year in which Tenant’s obligation to share therein commences and for the
calendar year in which such obligation ceases shall be prorated
  
                                                                 12


on a commercially reasonable basis determined by Landlord and consistent with generally accepted commercial property
accounting principles. Expenses such as taxes, assessments and insurance premiums that are incurred for an extended time
period shall be prorated based upon the time periods to which they apply so that the amounts attributed to the Premises relate
in a reasonable manner to the time period wherein Tenant has an obligation to share in Operating Expenses.

     9.6. In the event that the Building is less than fully occupied, Tenant acknowledges that Landlord may extrapolate those
particular items of Operating Expenses that vary depending on the occupancy of the Building to reflect the amount that would
have been incurred for those particular expenses had the entire Building been occupied during such period; provided , however,
that Landlord shall not recover more than one hundred percent (100%) of Operating Expenses. 

10. Taxes on Tenant’s Property .
      10.1. Tenant shall be responsible for any and all taxes levied against any personal property or trade fixtures placed by
Tenant in or about the Premises. Tenant shall not be deemed to be in default of its obligations under the preceding sentence in
the event that Tenant shall contest the validity of any such taxes by appellate or other proceedings permitted under Applicable
Laws, provided that: (a) any such contest is made reasonably and in good faith, (b) Tenant makes commercially reasonable 
provisions reasonably acceptable to Landlord (which shall include posting bond(s) or giving other security satisfactory to
Landlord if the Building or the Property are subjected to any liens arising out of such failure to pay or contest, with Tenant in
each case agreeing to discharge or bond over any such liens within 15 days after such liens arise) to protect Landlord, the
Building and the Property from any liabilities, costs, damages and expenses arising in connection with Tenant’s inability to pay,
or the contest of, such taxes, (c) Tenant agrees to indemnify, defend (with counsel reasonably acceptable to Landlord) and hold 
Landlord harmless from and against any and all liabilities, costs, damages and expenses arising in connection with Tenant’s
failure to pay, or contest of, such taxes as required by Applicable Law, and (d) Tenant promptly pays any and all such taxes in 
the event that it exhausts all available appeals without success or if such payment is required as a precondition to such contest.

      10.2. If (a) (i) any such taxes on Tenant’s personal property or trade fixtures are levied against Landlord or Landlord’s
property, or (ii) the assessed valuation of the Building or the Property is increased by inclusion therein of a value specifically 
attributed to Tenant’s personal property or trade fixtures, as evidenced by information provided in writing by the tax assessor,
and (b) Landlord, after written notice to Tenant, pays the taxes on Tenant’s personal property or trade fixtures, then Tenant
shall, upon demand, repay to Landlord the taxes so paid by Landlord.
  
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11. Security Deposit .
     11.1. Tenant shall deposit with Landlord on or before the Execution Date a letter of credit (the “ L/C Security ”) as the entire
security deposit (the “ Security Deposit ”), as follows:

            (a) Tenant shall provide Landlord, and maintain in full force and effect throughout the Term and until the date that is
ninety (90) days after the then-current Term Expiration Date, a letter of credit substantially in the form of Exhibit E issued by an
issuer reasonably satisfactory to Landlord, in the amount of the Security Deposit, with an initial term of at least one year.
Landlord may require the L/C Security to be replaced by an L/C Security issued by a different issuer at any time during the Term
if Landlord reasonably believes that the issuing bank of the L/C Security is or may soon become insolvent, in which event
Landlord shall cooperate with Tenant to arrange for the replacement of the L/C Security in a manner that does not require the
simultaneous issuance of two (2) letters of credit. If Tenant has actual notice, or Landlord notifies Tenant at any time, that any 
issuer of the L/C Security has become insolvent or placed into FDIC receivership, then Tenant shall promptly deliver to
Landlord (without the requirement of further notice from Landlord) substitute L/C Security issued by an issuer reasonably
satisfactory to Landlord, and otherwise conforming to the requirements set forth in this Article. As used herein with respect to
the issuer of the L/C Security, “insolvent” shall mean the determination of insolvency as made by such issuer’s primary bank
regulator (i.e., the state bank supervisor for state chartered banks; the OCC or OTS, respectively, for federally chartered banks
or thrifts; or the Federal Reserve for its member banks).

            (b) Landlord may draw upon the L/C Security, and hold and apply the proceeds for the payment of any Rent or any
other sum in default, or to compensate Landlord for any other loss or damage that Landlord may suffer by reason of Tenant’s
default, if: (i) a Default (as defined below) exists (or would have existed with the giving of notice and passage of applicable cure 
periods, but only if transmittal of a default notice is stayed or barred by applicable bankruptcy or other similar law), provided
that such draw pursuant to his clause (i) shall be limited to the amount that Landlord reasonably determines is required to cure 
such Default; (ii) as of the date forty-five (45) days before any L/C Security expires Tenant has not delivered to Landlord an 
amendment or replacement for such L/C Security, reasonably satisfactory to Landlord, extending the expiry date to the earlier of
(1) ninety (90) days after the then-current Term Expiration Date or (2) the date one year after the then-current expiry date of the
L/C Security; (iii) Tenant fails to pay (when and as Landlord reasonably requires) any bank charges for Landlord’s transfer of
the L/C Security; or (iv) the issuer of the L/C Security ceases, or announces that it will cease, to maintain an office in the city 
where Landlord may present drafts under the L/C Security (and fails to permit drawing upon the L/C Security by overnight
courier or facsimile). This Section does not limit any other provisions of this Lease allowing Landlord to draw the L/C Security
under specified circumstances. In the event of any such draw upon the L/C Security, Tenant shall within 10 days thereafter
provide Landlord with a replacement letter of credit, or amendment to the existing letter of credit increasing the amount of such
letter of credit, in the amount of L/C Security required hereunder, and Tenant’s failure to do so shall be a material breach of this
Lease. Landlord shall hold the proceeds of any draw not applied as set forth above as a cash Security Deposit as further
described below.

            (c) If Landlord transfers its interest in the Premises, then Landlord shall transfer the L/C Security to the transferee of
its interest, and Tenant shall at Tenant’s expense, within fifteen (15) business days after receiving a request from Landlord, 
deliver (and, if the issuer requires, Landlord shall consent to) an amendment to the L/C Security naming Landlord’s grantee as
substitute beneficiary. If the required Security Deposit changes while L/C Security is in force, then Tenant shall deliver (and, if
the issuer requires, Landlord shall consent to) a corresponding amendment to the L/C Security.
  
                                                                  14


           (d) If and to the extent Landlord is holding the proceeds of the L/C Security in cash from time to time, such cash shall
be held by Landlord as security for the faithful performance by Tenant of all of the terms, covenants and conditions of this
Lease to be kept and performed by Tenant during the period commencing on the Execution Date and ending upon the expiration
or termination of Tenant’s obligations under this Lease. If Tenant Defaults with respect to any provision of this Lease,
including any provision relating to the payment of Rent, then Landlord may (but shall not be required to) use, apply or retain all
or any part of the Security Deposit for the payment of any Rent or any other sum in Default, or to compensate Landlord for any
other loss or damage that Landlord may suffer by reason of Tenant’s Default as provided in this Lease. The provisions of this
Article shall survive the expiration or earlier termination of this Lease. In the event of bankruptcy or other debtor-creditor
proceedings against Tenant, any cash Security Deposit then being held by Landlord shall be deemed to be applied first to the
payment of Rent and other charges due Landlord for all periods prior to the filing of such proceedings. Landlord shall deliver or
credit to any purchaser of Landlord’s interest in the Premises the funds then held hereunder by Landlord, and thereupon (and
upon confirmation by the transferee of such funds, whether expressly or by written assumption of this Lease, generally)
Landlord shall be discharged from any further liability with respect to such funds. This provision shall also apply to any
subsequent transfers. If Tenant shall fully and faithfully perform every provision of this Lease to be performed by it, then the
Security Deposit, if any, or any balance thereof, shall be returned to Tenant (or, at Landlord’s option, to the last assignee of
Security Deposit, if any, or any balance thereof, shall be returned to Tenant (or, at Landlord’s option, to the last assignee of
Tenant’s interest hereunder) within 90 days after the expiration or earlier termination of this Lease. If and to the extent the
Security Deposit shall be in cash, Landlord shall hold the Security Deposit in an account at a banking organization selected by
Landlord; provided , however, that Landlord shall not be required to maintain a separate account for the Security Deposit, but
may intermingle it with other funds of Landlord. Landlord shall be entitled to all interest and/or dividends, if any, accruing on
the Security Deposit. Landlord shall not be required to credit Tenant with any interest for any period during which Landlord
does not receive interest on the Security Deposit.

12. Use .
     12.1. Tenant shall use the Premises for the purpose set forth in Section 2.7 , and shall not use the Premises, or permit or
suffer the Premises to be used, for any other purpose without Landlord’s prior written consent, which consent Landlord may
withhold in its sole and absolute discretion.

     12.2. Tenant shall not use or occupy the Premises in violation of Applicable Laws; zoning ordinances; or the certificate of
occupancy issued for the Building or the Property, and shall, upon five (5) days’ written notice from Landlord, discontinue any
use of the Premises that is declared or claimed by any Governmental Authority having jurisdiction to be a violation of any of the
above, or that in Landlord’s reasonable opinion violates any of the above. Tenant shall comply with any direction of any
Governmental Authority having jurisdiction that shall, solely by reason of the nature of Tenant’s use or occupancy of the
Premises (other than for general office or laboratory use), impose any duty upon Tenant or Landlord with respect to the
Premises or with respect to the use or occupation thereof.
  
                                                                 15


      12.3. Tenant shall not do or permit to be done anything that will invalidate or increase the cost of any fire, environmental,
extended coverage or any other insurance policy covering the Building or the Property, and shall comply with all commercially
reasonable and customary rules, orders, regulations and requirements of the insurers of the Building and the Property, and
Tenant shall promptly, upon demand, reimburse Landlord for any additional premium charged for such policy solely by reason
of Tenant’s failure to comply with the provisions of this Article, or cease the applicable activity, to the extent that ceasing such
activity does in fact prevent such cost increase from occurring. The use of the Premises for office or laboratory uses, generally,
will not result in a breach of the provisions of this paragraph.

     12.4. Tenant shall keep all doors opening onto public corridors closed, except when in use for ingress and egress.

     12.5. No additional locks or bolts of any kind shall be placed upon any of the doors or windows by Tenant, nor shall any
changes be made to existing locks or the mechanisms thereof without Landlord’s prior written consent. Tenant shall, upon
termination of this Lease, return to Landlord all keys to offices and restrooms either furnished to or otherwise procured by
Tenant. In the event any key so furnished to Tenant is lost, Tenant shall pay to Landlord the cost of replacing the same or of
changing the lock or locks opened by such lost key if Landlord shall deem it necessary to make such change.

     12.6. No awnings or other projections shall be attached to any outside wall of the Building. No curtains, blinds, shades or
screens shall be attached to or hung in, or used in connection with, any exterior or atrium window or door of the Premises other
than Landlord’s standard window coverings as described in the Tenant Manual. Neither the interior nor exterior of any
windows shall be coated or otherwise sunscreened without Landlord’s prior written consent, nor shall any bottles, parcels or
other articles be placed on the windowsills. No equipment, furniture or other items of personal property shall be placed on any
exterior balcony without Landlord’s prior written consent.

     12.7. No sign, advertisement or notice (“ Signage ”) shall be exhibited, painted or affixed by Tenant on any part of the
Premises or the Building without Landlord’s prior written consent, which may be withheld in Landlord’s sole discretion, except
as expressly set forth in this Section 12.7. Tenant shall be entitled to install and maintain, at its sole cost and expense, (1) one 
exterior sign identifying Tenant on the facade of the Building to be located within the area designated on Exhibit L attached
hereto, and (2) interior entry signage on doors to the Premises in Landlord’s reasonable discretion (to the extent visible from
Common Areas) and in a manner consistent with Landlord’s reasonable Building Standards, subject in each case to all
Applicable Laws, codes and ordinances and Landlord’s reasonable approval with regards to installation, size, design, location
and other reasonable criteria (provided, however, the standard corporate lettering and logo of Tenant are hereby approved). For
any Signage, Tenant shall, at Tenant’s own cost and expense, (a) acquire all permits for such Signage in compliance with 
Applicable Laws and (b) design, fabricate, install and maintain such Signage in a first-class condition. Tenant shall be
responsible for removing any of Tenant’s Signage upon the expiration
  
                                                                 16
                                                                 16


or earlier termination of this Lease. The directory tablet shall be inscribed, painted or affixed for Tenant by Landlord at
Landlord’s sole cost and expense, and shall be of a size, color and type and be located in a place acceptable to Landlord. The
directory tablet shall be provided exclusively for the display of the name and location of tenants only. Tenant shall not place
anything on the exterior of the corridor walls or corridor doors other than Landlord’s standard lettering.

     12.8. Tenant shall only place equipment within the Premises with floor loading consistent with the Building’s structural
design (which is 100 psf) without Landlord’s prior written approval, and such equipment shall be placed in a location designed
to carry the weight of such equipment.

     12.9. Tenant shall cause any equipment or machinery to be installed in the Premises so as to reasonably prevent sounds or
vibrations therefrom from extending into the Common Areas or other offices in the Property.

     12.10. Tenant shall not (a) do or permit anything to be done in or about the Premises that shall in any way unreasonably 
obstruct or interfere with the rights of other tenants or occupants of the Property, or injure them, (b) use or allow the Premises 
to be used for unlawful purposes, (c) cause, maintain or permit any nuisance or waste in, on or about the Property or (d) take 
any other action that would in Landlord’s reasonable determination in any manner unreasonably and adversely affect other
tenants’ quiet use and enjoyment of their space or adversely impact their ability to conduct business in a professional and
suitable work environment for office and laboratory uses.

      12.11. Landlord shall be responsible for ensuring the Common Areas comply with the Americans with Disabilities Act, 42
U.S.C. § 12101, et seq., and any state and local accessibility laws, codes, ordinances and rules (collectively, and together with 
regulations promulgated pursuant thereto, the “ ADA ”) to (which cost may be included in Operating Expenses) and that the
Landlord Demising Work is performed in compliance with the ADA. Subject to the foregoing, Tenant shall be responsible for all
liabilities, costs and expenses arising out of or in connection with the compliance of the Premises with the ADA, and Tenant
shall indemnify, save, defend (at Landlord’s option and with counsel reasonably acceptable to Landlord) and hold Landlord and
its affiliates, employees, agents and contractors; and any lender, mortgagee or beneficiary (each, a “ Lender ” and, collectively
with Landlord and its affiliates, employees, agents and contractors, the “ Landlord Indemnitees ”) harmless from and against
any demands, claims, liabilities, losses, costs, expenses, actions, causes of action, damages or judgments, and all reasonable
expenses (including reasonable attorneys’ fees, charges and disbursements) incurred in investigating or resisting the same
(collectively, “ Claims ”) arising out of any such failure of the Premises to comply with the ADA. This Section (as well as any
other provisions of this Lease dealing with indemnification of the Landlord Indemnitees by Tenant shall be deemed to be
modified in each case by the insertion in the appropriate place of the following: “except as otherwise provided in Mass. G.L. Ter.
Ed., C. 186, Section 15.” The provisions of this Section shall survive the expiration or earlier termination of this Lease.
  
                                                                 17


      12.12. Tenant shall establish and maintain a chemical safety program administered by a licensed, qualified individual in
accordance with the requirements of the Massachusetts Water Resources Authority (“ MWRA ”) and any other applicable
Governmental Authority. Tenant shall be solely responsible for all costs incurred in connection with such chemical safety
program, and Tenant shall provide Landlord with such documentation as Landlord may reasonably require evidencing Tenant’s
compliance with the requirements of (a) the MWRA and any other applicable Governmental Authority with respect to such 
chemical safety program and (b) this Section. Tenant shall not introduce anything into the sewer system serving the Building 
(x) in violation Applicable Laws. Landlord agrees to reasonably cooperate with Tenant, at no unreimbursed cost to Landlord, in 
order for Tenant to obtain any MWRA permit and wastewater treatment operator license required for Tenant’s operations.
Tenant shall reimburse Landlord within ten (10) business days after demand for any third party costs reasonably incurred by 
Landlord in cooperating with Tenant pursuant to this Section.
13. Rules and Regulations, CC&Rs, Parking Facilities and Common Areas .
      13.1. Tenant shall have the non-exclusive right, in common with others, to use the Common Areas in conjunction with
Tenant’s use of the Premises for the Permitted Use (including without limitation such Common Areas as are reasonably
designated by Landlord for the connection of any equipment located in off-floor mechanical areas that are contained within the
Premises to the applicable occupied floor of the Premises), and such use of the Common Areas and Tenant’s use of the
Premises shall be subject to the rules and regulations and tenant manual governing Alterations, each as adopted by Landlord
and initially attached hereto as Exhibit F , together with such other reasonable and nondiscriminatory rules and regulations as
are hereafter promulgated by Landlord of which Tenant is given prior written notice (collectively, the “ Rules and Regulations
”), provided, however, that in the case of any conflict between the provisions of this Lease and any such Rules and
Regulations, the provisions of this Lease shall control. Tenant shall faithfully observe and comply with the Rules and
Regulations. Landlord shall use reasonable efforts to enforce the Rules and Regulations against Tenant or any other tenant of
the Building or Property, but shall have no responsibility for any violations thereof. Landlord shall not enforce the Rules and
Regulations in a discriminatory manner against Tenant.

     13.2. This Lease is subject to any recorded covenants, conditions or restrictions on the Property (the “ CC&R ”), to the
Development Approvals (as defined on Exhibit D ), and to any other matters of record, in each case as the same may be
amended, amended and restated, supplemented or otherwise modified from time to time (collectively, the “ Property Operations
Agreements ”; provided that any such amendments, restatements, supplements or modifications do not materially modify
Tenant’s rights or obligations or Landlord’s obligations hereunder. Each of Landlord and Tenant, in the exercise of their
respective rights and the performance of their respective obligations pursuant to this Lease, shall observe and comply with all
requirements of the CC&R and Development Approvals. The CC&R covers certain areas shown on the site plan attached as
Exhibit K , including landscaping, private drives, streets, parks, open space, walkways, sidewalks, the ice skating rink, the water
fountain, the sky bowl and other improvements and appurtenances located thereon and related thereto, including the Building
and other buildings located on the Property thereon, all commonly referred to as “Kendall Square”, and expenses payable by
the Building under the CC&R (which are based on the Lot’s proportionate share of Kendall Square) are included in Operating
Expenses.
  
                                                                 18


     13.3. Tenant shall be permitted access to the Building and Premises on a 24 hour per day, 7 day per week basis, subject to
matters described in Section 41.6 of this Lease and Landlord’s reasonable security measures, and subject to Landlord’s rights
pursuant to this Lease to temporarily prohibit, restrict or limit access to the Building or the Premises in emergency situations if
Landlord determines, in its reasonable discretion, that it is necessary or advisable to do so in order to prevent or protect against
death or injury to persons or damage to property.

      13.4. It is intended that all Rent payable by Tenant to Landlord, which includes all sums, charges, or amounts of whatever
nature to be paid by Tenant to Landlord in accordance with the provisions of this Lease, shall qualify as “rents from real
property” within the meaning of both Sections 512(b)(3) and 856(d) of the Code and the U.S. Department of Treasury 
Regulations promulgated thereunder (the “Regulations”). If Landlord, in its sole discretion, determines that there is any risk that
all or part of any Rent shall not qualify as “rents from real property” for the purposes of Section 512(b)(3) or 856(d) of the Code 
and the Regulations, Tenant agrees (i) to cooperate with Landlord by entering into such amendment or amendments to this 
Lease as Landlord reasonably deems necessary to qualify all Rent as “rents from real property,” and (ii) to permit an assignment 
of this Lease; provided, however, that any adjustments required under this Section shall be made so as to produce the
substantially equivalent (in economic terms) Rent as payable before the adjustment.

     13.5. (a) Tenant shall have a non-exclusive, irrevocable license to use up to a total of 189 unreserved parking spaces (i.e.,
determined by multiplying the Rentable Area of the Premises by 0.0015) from and after the Phase 1 Rent Commencement Date (“ 
Tenant’s Parking Spaces ”) in the underground parking garage on the Property in common with other tenants of the Property at
the market rate for such comparable parking lots in commercial garages in the East Cambridge market, as reasonably determined
by Landlord (as of the date hereof, such rate being Two Hundred Sixty and 00/100 Dollars ($260.00) per parking space per
month), which Tenant shall pay simultaneously with payments of Base Rent as Additional Rent commencing on the Phase 1
Rent Commencement Date unless and except to the extent that Landlord directs Tenant to pay the same to a Garage Operator as
defined below. Upon 30 days’ notice given prior to the Phase 1 Rent Commencement Date, Tenant will have the option of
designating any number of Tenant’s Parking Spaces between the maximum number set forth above and the portion of Tenant’s
Parking Spaces allocable to the Phase 1 Premises (based on Rentable Area) as being licenses as of the Phase 1 Rent
Commencement Date (with the remainder of Tenant’s Parking Spaces being treated as allocable to the Phase 2 Premises).
Tenant’s failure to make any such election prior to the Phase 1 Premises Rent Commencement Date shall be deemed to be an
election to allocate such spaces on a prorated basis between the Phase 1 Premises and Phase 2 Premises. Tenant shall pay for
the license to use Tenant’s Parking Spaces regardless of whether such spaces are in fact used by Tenant; provided, however,
that Tenant shall have the right to terminate its license with respect to any such spaces on 30 days’ prior written notice to
Landlord. Any such termination of Tenant’s license hereunder in whole or in part shall be irrevocable and Landlord shall have
no further right to provide Tenant with spaces for which such rights have terminated, provided that Landlord shall use
reasonable efforts to make additional spaces available to Tenant, subject to availability, on a revocable, month-to-month
  
                                                                19


basis as reasonably requested by Tenant on at least 30 days’ prior notice (and otherwise on the terms and conditions contained
in this Section 13.5, including the limitation on total spaces licensed by Tenant set forth above). All of Tenant’s Parking Spaces
shall be located in the underground parking structure in the Building (the “ Garage ”), which Garage may be owned or leased by
or to a third-party Garage operator from time to time. The owner or operator of the Garage from time to time is herein referred to
as the “ Garage Operator ,” and the Tenant’s Parking Spaces are sometimes herein referred to as the “ Garage Parking Spaces .” 
Landlord covenants and agrees that if the Garage is conveyed or leased by Landlord to any Garage Operator, such conveyance
shall be subject to a lease, permanent easement or similar instrument by and between Landlord and the Garage Operator so that
the Tenant shall have, from and after the Phase 1 Rent Commencement Date, throughout the Term, the right to use the Garage
Parking Spaces, subject to the terms of this Lease.

           (b) Landlord or the Garage Operator, as applicable, shall have the right, from time to time but not more often than
every two (2) years, to relocate, on a temporary basis (not to exceed thirty (30) days) as may be necessary to effect repairs and 
improvements to the Garage or for other business reasons, parking spaces located in the Garage to another location within 1,000
feet of the Property. Except to the extent resulting from their negligence or willful misconduct and subject to Section 23.7 ,
neither Landlord nor the Garage Operator shall be responsible for money, jewelry, automobiles or other personal property lost in
or stolen from the Garage, regardless of whether such loss or theft occurs when the Garage or other areas therein are locked or
otherwise secured against entry, or liable for any loss, injury or damage to persons using the Garage or automobiles or other
property therein, it being agreed that the use of the Garage and the Tenant’s Parking Spaces shall otherwise be at the sole risk
of Tenant and its employees, visitors and guests. Landlord and the Garage Operator shall have the right from time to time to
promulgate Rules and Regulations regarding the Garage, the Tenant’s Parking Spaces and the use thereof, including, but not
limited to, Rules and Regulations controlling the flow of traffic to and from various parking areas, the angle and direction of
parking and the like, and to implement valet parking. Tenant shall comply with and cause its employees, visitors and guests to
comply with all such Rules and Regulations as well as reasonable additions and amendments thereto.

          (c) Landlord or the Garage Operator, as applicable, may elect to provide parking cards or keys to control access to the
Garage. In such event, Landlord or the Garage Operator shall provide Tenant with one card or key for each Tenant’s Parking
Space that Tenant is leasing hereunder, provided that Landlord or the Garage Operator shall have the right to require Tenant or
its employees to place a reasonable deposit (not to exceed Twenty-Five Dollars ($25.00)) on such access cards or keys and to
pay a reasonable fee for any lost or damaged cards or keys. Tenant, at its sole cost and expense, may obtain extra cards and
keys from Landlord or the Garage Operator, as applicable, if any cards are lost, stolen or destroyed.

      13.6. Landlord reserves the right to modify the Common Areas, including the right to add or remove exterior and interior
landscaping. Tenant acknowledges that Landlord specifically reserves the right to allow the exclusive use of corridors and
restroom facilities located on specific floors to one or more tenants occupying such floors; provided , however, that Tenant
shall not be deprived of the access to or use of the corridors reasonably required to serve the Premises or of restroom facilities
serving each floor upon which any portion of the Premises is located.
  
                                                                20


    13.7. Subject to the terms of this Lease including the Rules and Regulations and the rights of other tenants of the Building,
Tenant shall have the non-exclusive right to access the freight loading dock, at no additional cost.

14. Property Control by Landlord .
     14.1. Landlord reserves full control over the Building and Property to the extent not inconsistent with Tenant’s use and
enjoyment of the Premises as provided by this Lease. Subject to the foregoing, this reservation includes Landlord’s right to
convert the Building to a condominium form of ownership; add or eliminate a portion of the Property; grant easements and
licenses to third parties; maintain or establish ownership of the Building separate from fee title to the Property; make additions
to or reconstruct portions of the Building; install, use, maintain, repair, replace and relocate for service to the Premises and other
parts of the Building or the Property pipes, ducts, conduits, wires and appurtenant fixtures, wherever located in the Premises,
the Building or elsewhere at the Property; and alter or relocate any other Common Area or facility, including private drives,
lobbies and entrances. Landlord will use reasonable efforts to ensure that any work undertaken in the Premises by Landlord
shall (except in an emergency) be undertaken in a manner that will not unreasonably interfere with Tenant’s operations.

     14.2. Possession of those existing areas of the Premises necessary for utilities, services, safety and operation of the
Building is reserved to Landlord.

     14.3. Tenant shall, at Landlord’s request, promptly execute such further documents, in form and substance reasonably
acceptable to the parties, as may be reasonably appropriate to assist Landlord in the performance of its obligations hereunder;
provided that Tenant need not execute any document that creates additional liability for Tenant or that deprives Tenant of the
quiet enjoyment and use of the Premises as provided for in this Lease.

      14.4. Landlord may, at any and all reasonable times during non-business hours (or during business hours, if (a) with 
respect to Subsections 14(u) through 14.4(y) , Tenant so requests, and (b) with respect to Subsection 14.4(z) , if Landlord so
requests), and upon twenty-four (24) hours’ prior notice ( provided that no time restrictions shall apply or advance notice be
required if an emergency necessitates immediate entry), enter the Premises to (u) inspect the same and to determine whether 
Tenant is in compliance with its obligations hereunder, (v) supply any service Landlord is required to provide hereunder, 
(w) alter, improve or repair any portion of the Building other than the Premises for which access to the Premises is reasonably 
necessary,(x) post notices of nonresponsibility, (y) access the telephone equipment, electrical substation and fire risers and 
(z) show the Premises to prospective and actual lenders, purchasers or, during the final year of the Term, tenants. In connection 
with any such alteration, improvement or repair as described in Subsection 14.4(w) , Landlord may erect in the Premises or
elsewhere in the Property scaffolding and other structures reasonably required for the alteration, improvement or repair work to
be performed. Notwithstanding anything to the contrary set forth herein, neither Landlord, nor Landlord’s agents,
representatives, contractors or employees may enter any portion of the Premises reasonably designated from time to time by
Tenant as a
  
                                                                 21


security area (not to exceed 35,000 square feet of Rentable Area in the aggregate, consisting of up to 25,000 square feet of
Rentable Area for a vivarium and up to 10,000 square feet of Rentable Area for a data center) without being accompanied by a
representative of Tenant, except in the case of an emergency, provided that such areas are clearly labeled as such and Landlord
is given at least 10 business days’ prior written notice of the location of such areas. In no event shall Tenant’s Rent abate as a
result of Landlord’s activities pursuant to this Section; provided , however, that all such activities shall be conducted in such a
manner so as to cause as little interference to Tenant as is reasonably possible. Landlord shall at all times retain a key with
which to unlock all of the doors in the Premises. If an emergency necessitates immediate access to the Premises, Landlord may
use whatever force is necessary to enter the Premises, and any such entry to the Premises shall not constitute a forcible or
unlawful entry to the Premises, a detainer of the Premises, or an eviction of Tenant from the Premises or any portion thereof.

15. Quiet Enjoyment . So long as Tenant is not in Default under this Lease, Landlord or anyone acting through or under
Landlord shall not disturb Tenant’s use or occupancy of the Premises or the exercise of Tenant’s rights hereunder in
accordance with this Lease, except as permitted by this Lease.

16. Utilities and Services .
      16.1. Tenant shall pay for all water (including the cost to service, repair and replace reverse osmosis, de-ionized and other
treated water), gas, heat, light, power, telephone, internet service, cable television, other telecommunications and other utilities
supplied to the Premises, together with any fees, surcharges and taxes thereon. Tenant shall, promptly after the Term
Commencement Date as part of the Tenant Improvements, install separate meters, or if separate direct metering is not possible,
sub- or check- meters for any such utilities provided to the Premises (other than those utilities that are used to supply Landlord
services, which are included in Operating Expenses). If any such utility is separately metered, Tenant shall pay the charge
therefore directly to the utility service provider when due. If any such utility is sub- or check-metered from time to time, then
Tenant shall pay for all such charges based on Landlord’s reading of such sub- or check-meters within 30 days after invoice. If,
notwithstanding the foregoing, any such utility is not separately or sub- or check-metered from time to time, then Tenant shall
pay to Landlord within 30 days after invoice for such charges based on Tenant’s Share of such charges provided to the
Building, or Landlord may, at its option, monitor the usage of such utilities by Tenant and charge Tenant with the cost of
purchasing, installing and monitoring such metering equipment, which cost shall be paid by Tenant as Additional Rent. At any
purchasing, installing and monitoring such metering equipment, which cost shall be paid by Tenant as Additional Rent. At any
time that Tenant is paying Landlord for the foregoing utilities based on Tenant’s Share, Landlord shall have the right to require
Tenant to pay 1/12th of Landlord’s reasonable estimate of such charges for the applicable calendar year during the term on a
monthly basis, together with payments of Base Rent, and shall reconcile such payments annually. To the extent that Tenant
uses more than Tenant’s Pro Rata Share of the Building of any utilities and such utilities are not separately metered or
submetered, then Tenant shall pay Landlord for Tenant’s Share of such utilities to reflect such excess. In the event that the
Building is less than fully occupied and Tenant is not then separately metered or sub- or check-metered for any utility, Tenant
acknowledges that Landlord may extrapolate utility usage that varies depending on the occupancy of the Building, by dividing
(a) the total cost of utility usage by (b) the Rentable Area of the Lab Building that is occupied, then multiplying (y) the resulting 
quotient by (z) ninety-five
  
                                                                 22


percent (95%) of the total Rentable Area of the Lab Building. Tenant shall pay Tenant’s Share of the product of (y) and (z), 
subject to adjustment based on actual usage as reasonably determined by Landlord; provided , however, that Landlord shall
not recover more than one hundred percent (100%) of such utility costs. 

     16.2. Landlord shall not be liable for, nor shall any eviction of Tenant or default of Landlord result from, the failure to
furnish any utility or service, regardless of the cause, including accident; breakage; strike, lockout or other labor disturbance or
furnish any utility or service, regardless of the cause, including accident; breakage; strike, lockout or other labor disturbance or
labor dispute of any character; act of terrorism; shortage of materials, which shortage is not unique to Landlord or Tenant, as
the case may be; failure by a third party to deliver gas, oil or another suitable fuel supply; or Landlord’s inability by exercise of
reasonable diligence to obtain gas, oil or another suitable fuel; governmental regulation, moratorium or other governmental
action, inaction or delay; or other causes described in Section 41.6 of this Lease or Landlord’s negligence. In the event of such
failure, Tenant shall not be entitled to termination of this Lease or any abatement or reduction of Rent, nor shall Tenant be
relieved from the operation of any covenant or agreement of this Lease. Notwithstanding anything to the contrary in this Lease,
if, for more than five (5) consecutive business days following written notice to Landlord and, for any reason other than matters 
described in Section 41.6 of this Lease or by an act or omission in violation of this Lease by Tenant or by any negligence of any 
of Tenant’s agents, employees, contractors, invitees, successors or others using the Premises with Tenant’s expressed or
implied permission, the provision of elevator, HVAC, plumbing, or utilities to all or a material portion of the Premises that
Landlord must provide pursuant to this Lease is interrupted, then Tenant’s Base Rent and Operating Expenses (or, to the extent
that less than all of the Premises are affected, a proportionate amount (based on the Rentable Area of the Premises that is
rendered unusable) of Base Rent and Operating Expenses) shall thereafter be abated until the Premises are again usable by
Tenant for the Permitted Use (and the Property Management Fee shall be reduced for such period to reflect any such reduction
in Base Rent); provided , however, that, if Landlord provides substitute elevator, HVAC, plumbing or utilities reasonably
suitable for Tenant’s continued use and occupancy of the Premises for the Permitted Use (e.g., supplying potable water or
portable air conditioning equipment), then neither Base Rent nor Operating Expenses shall be abated so long as Landlord is
diligently pursuing the restoration of such elevator, HVAC, plumbing or utilities. In the event of any interruption of elevator,
HVAC, plumbing, or other utilities that Landlord must provide pursuant to this Lease, regardless of the cause, Landlord shall
diligently pursue the restoration of such elevator, HVAC, plumbing, or other utilities. Notwithstanding anything in this Lease to
the contrary, but subject to Article 24 (which shall govern in the event of a casualty), so long as Landlord is diligently pursuing
the restoration, the provisions of this Section shall be Tenant’s sole recourse and remedy in the event of an interruption of
utilities or Landlord services to the Premises.

     16.3. Tenant shall pay for, prior to delinquency of payment therefor, any services that may be furnished to the Premises
during or, if Tenant occupies the Premises after the expiration or earlier termination of the Term, after the Term, beyond those
services provided by Landlord, including telephone, internet service, cable television and other telecommunications, together
with any fees, surcharges and taxes thereon. Tenant shall pay for such services directly to the supplier of such services.
  
                                                                 23


     16.4. Tenant shall not, without Landlord’s prior written consent, which shall not be unreasonably withheld, delayed or
conditioned, use any device in the Premises (including data processing machines) that will in any way (a) increase the amount 
of ventilation, air exchange, gas, steam, electricity or water required or consumed in the Premises based upon Tenant’s Pro Rata
Share of the Building beyond the existing capacity of the Building usually furnished or supplied for the use set forth in
Section 2.7 or (b) exceed Tenant’s Pro Rata Share of the Building’s capacity to provide such utilities or services.

      16.5. If Tenant shall require utilities or services in excess of those usually furnished or supplied for tenants in similar
spaces in the Building or the Property by reason of Tenant’s equipment or extended hours of business operations, then Tenant
shall first procure Landlord’s consent for the use thereof, which consent Landlord may condition upon the availability of such
excess utilities or services, and Tenant shall pay as Additional Rent an amount equal to Landlord’s actual cost (as may be
reasonably estimated by Landlord) of providing such excess utilities and services to the extent not otherwise paid by Tenant
pursuant to the provisions of Section 16.1, above. 

    16.6. Landlord shall provide water in Common Areas for lavatory and landscaping purposes only, which water shall be
from the local municipal or similar source. Tenant shall not use or consume water provided to the Common Areas for any
purpose other than ordinary or reasonable lavatory purposes.

      16.7. Subject to the provisions of Section 16.2, above, Landlord reserves the right to stop service of the elevator, plumbing, 
HVAC and other utility systems for reasonable periods when Landlord reasonably deems necessary or desirable due to
accident, emergency or the need to make repairs, alterations or improvements, until such repairs, alterations or improvements
shall have been completed. Landlord shall use reasonable efforts to schedule and perform any such repairs, alterations or
improvements outside of business hours to the extent the same will adversely affect Tenant’s ability to conduct its business in
the Premises.

    16.8. Subject to the provisions of this Lease governing Alterations, Tenant, at its sole cost and expense, shall have the
appurtenant right to install and maintain, at no additional charge, one emergency generator, together with connections to
existing Building fuel piping to serve the same (collectively, the “ Generator ”) serving the Premises as reasonably required for
Tenant’s operations in the Premises, subject to Landlord’s reasonable approval with respect to specifications of such generator
and the plans for such installation, in a location within the Rooftop Installation Area or in the Garage as may be mutually agreed
upon between Landlord and Tenant. Tenant shall be responsible for obtaining and maintaining, at its sole cost and expense,
any permits or approvals required in connection with the installation and maintenance of the Generator. The Generator shall be
screened from view in a manner consistent with the standards for a first class office, laboratory and research and development
park in Kendall Square. The installation of the Generator shall be in compliance with applicable laws, codes and ordinances and
shall not interfere with or compromise the integrity of the Building.
  
  
                                                                24


     16.9. Landlord shall maintain and operate the Building HVAC systems and shall permit Tenant to connect to the same at
the Premises points of connection for Tenant’s use within the Premises and shall furnish HVAC to the Common Areas for
reasonably comfortable occupancy of the same throughout the term of this Lease. To the extent that Tenant requires HVAC
services in excess of those provided by connection to the Building HVAC systems, Tenant shall install and maintain
supplemental HVAC systems in accordance with the provisions of this Lease.

      16.10. For any utilities serving the Premises for which Tenant is billed directly by such utility provider, Tenant agrees to
furnish to Landlord (a) any invoices or statements for such utilities, (b) any other utility usage information received by Tenant 
and reasonably requested by Landlord, and (c) any ENERGY STAR® Statement of Performance (or similar comprehensive utility
usage report (e.g., related to Labs 21), if requested by Landlord) and any other information reasonably requested by Landlord
for the immediately preceding year, all within ninety (90) days after Landlord’s request made no more often than one (1) time per 
year. Tenant shall retain records of utility usage at the Premises, including invoices and statements from the utility provider, for
at least sixty (60) months, or such shorter period of time as may be requested by Landlord. Tenant acknowledges that any utility 
information for the Premises, the Building and the Property may be shared with third parties, including Landlord’s consultants
and Governmental Authorities.

     16.11. Tenant shall have 24-hour access to the freight elevator and freight loading dock serving the Premises in common
with other tenants of the Building at no additional cost (other than to the extent includable in Operating Expenses) and shall
have the right, in common with others, to use the passenger elevators in the Building.

17. Alterations .
      17.1. Tenant shall make no alterations, additions or improvements other in or to the Premises or engage in any
construction, demolition, reconstruction, renovation, or other work (whether major or minor) of any kind in, at, or serving the
Premises (“ Alterations “, which shall include Tenant Improvements) without Landlord’s prior written approval, which approval
Landlord shall not unreasonably withhold, condition or delay; provided , however, that in the event any proposed Alteration
adversely affects (a) any structural portions of the Building, including exterior walls, roof, foundation, foundation systems 
(including barriers and subslab systems), or core of the Building, (b) the exterior of the Building or (c) other than in a minor 
manner not adversely affecting the same, any Building systems, including elevator, plumbing, air conditioning, heating,
electrical, security, life safety and power, then Landlord may withhold its approval with respect thereto in its sole and absolute
discretion. Tenant shall, in making any such Alterations, use only those architects, contractors, suppliers and mechanics of
which Landlord has given prior written approval, which approval shall not be unreasonably withheld, delayed or conditioned. In
seeking Landlord’s approval, Tenant shall provide Landlord, at least fourteen (14) days in advance of any proposed 
construction, with plans, specifications, stamped engineering drawings and calculations by Tenant’s engineer of record or
architect or record, certified as being in accordance with Applicable Laws (including connections to the Building’s structural
system, modifications to the Building’s envelope, non-structural penetrations in slabs or walls, and modifications or tie-ins to
life safety systems), work contracts, requests for laydown areas and such other information concerning the nature and cost of
the Alterations as Landlord may reasonably request. In no event shall Tenant use or Landlord be required to approve any
architects, consultants, contractors, subcontractors or material
  
                                                                25


suppliers that Landlord reasonably believes is likely to cause labor disharmony. Landlord may condition its approval of any
Alterations on Tenant’s removing the same upon the expiration or earlier termination of this Lease or Tenant’s right to
possession of the Premises, at Tenant’s sole cost, provided that Landlord so notifies Tenant at the time that Landlord approves
the plans for such Alterations. Notwithstanding the foregoing, Tenant may make non-structural minor and cosmetic changes to
the Premises (“ Cosmetic Alterations ”) without Landlord’s consent; provided that (y) the cost of any Cosmetic Alterations do 
not exceed Fifty Thousand Dollars ($50,000) in any one instance, (z) such Cosmetic Alterations do not (i) require any structural 
or other substantial modifications to the Premises, (ii) require any changes to, or adversely affect, the Building systems, 
(iii) affect the exterior of the Building or (iv) trigger any requirement under Applicable Laws that would require Landlord to make 
any alteration or improvement to the Building or the Property. Tenant shall give Landlord at least ten (10) days’ prior written
notice of any Cosmetic Alterations.

      17.2. Tenant shall not construct or permit to be constructed partitions or other obstructions that are likely to unreasonably
interfere with free access to mechanical installation or service facilities of the Building or with other tenants’ components
located within the Building, or interfere with the moving of Landlord’s equipment to or from the enclosures containing such
installations or facilities.

     17.3. Tenant shall accomplish any work performed on the Premises or the Building in such a manner as to permit any life
safety systems to remain fully operable at all times.

     17.4. Any work performed on the Premises, the Building or the Property by Tenant or Tenant’s contractors shall be done at
such times and in such manner as Landlord may from time to time reasonably designate. Tenant covenants and agrees that all
work done by Tenant or Tenant’s contractors shall be performed in full compliance with Applicable Laws. Within thirty
(30) days after completion of any Alterations (other than Cosmetic Alterations), Tenant shall provide Landlord with complete 
“as-built” drawing print sets, project specifications and shop drawings, and electronic CADD files on disc (or files in such other
current format in common use as Landlord reasonably approves or requires) showing any changes in the Premises. Any such
“as-built” plans shall show the applicable Alterations as an overlay on the Building as-built plans, to the extent provided by
Landlord to Tenant for such purpose.

    17.5. Before commencing any Alterations, Tenant shall give Landlord at least fourteen (14) days’ prior written notice of the
proposed commencement of such work and shall, if requested by Landlord for any Alterations costing more than $200,000,
when taken together with any related Alterations being made as part of the same project, secure, at Tenant’s own cost and
expense, a performance, completion and lien indemnity bond reasonably satisfactory to Landlord for such work.

      17.6. Tenant shall repair any damage to the Premises caused by Tenant’s removal of any property from the Premises at the
expiration or earlier termination of the Term. The provisions of this Section shall survive the expiration or earlier termination of
this Lease.

     17.7. (a) The Premises shall at all times remain the property of Landlord and shall be surrendered to Landlord upon the
expiration or earlier termination of this Lease.
  
                                                                 26


           (b) All Alterations, Signage, attached equipment, decorations, fixtures, movable laboratory casework and related
appliances, trade fixtures, additions and improvements attached to or built into the Premises, made by either of the Parties
(including all floor and wall coverings, built-in cabinet work and paneling, sinks and related plumbing fixtures, laboratory
benches, exterior venting fume hoods and walk-in freezers and refrigerators, ductwork, conduits, electrical panels and circuits),
shall (unless, prior to such construction or installation, Landlord in writing elects otherwise) become the property of Landlord
upon the expiration or earlier termination of the Term, and shall remain upon and be surrendered with the Premises as a part
thereof.

          (c) Subject to Section 17.7(b) and except as to those items listed on Exhibit G attached hereto (which Exhibit G may be
updated by Tenant from and after the Term Commencement Date, subject to Landlord’s written consent), all Alterations,
together with all additions and accessories thereto, installed in and upon the Premises shall be and remain the property of
Landlord and shall not be moved by Tenant at any time during the Term.

          (d) Notwithstanding any other provision of this Article to the contrary, in no event shall Tenant remove any
improvement from the Premises as to which Landlord contributed payment, including the Tenant Improvements, without
Landlord’s prior written consent, which consent Landlord may withhold in its sole and absolute discretion. Landlord may
require Tenant to remove Specialty Alterations prior to the expiration or earlier termination of the Term; provided, however, that
Tenant shall not be required to remove any Specialty Alterations to the extent the same are shown on Exhibit B-2 attached
hereto. For purposes of this Lease, “ Specialty Alterations ” shall mean Alterations that are not consistent with standard office
or laboratory installations.

           (e) If Tenant shall fail to remove any of its effects from the Premises prior to termination of this Lease, then Landlord
may, at its option, remove the same in any manner that Landlord shall choose and store such effects without liability to Tenant
for loss thereof or damage thereto, and Tenant shall pay Landlord, upon demand, any costs and expenses incurred due to such
removal and storage or Landlord may, at its sole option and without notice to Tenant, sell such property or any portion thereof
at private sale and without legal process for such price as Landlord may obtain and apply the proceeds of such sale against any
at private sale and without legal process for such price as Landlord may obtain and apply the proceeds of such sale against any
(i) amounts due by Tenant to Landlord under this Lease and (ii) any expenses incident to the removal, storage and sale of such 
personal property.

     17.8. Other than with respect to the Tenant Improvements, Tenant shall pay to Landlord an amount equal to three percent
(3%) of the cost to Tenant of all Alterations (other than Tenant Improvements and Cosmetic Alterations) to cover Landlord’s
overhead and expenses for plan review, coordination, scheduling and supervision thereof. For purposes of payment of such
sum, Tenant shall submit to Landlord copies of all bills, invoices and statements covering the costs of such charges,
accompanied by payment to Landlord of the fee set forth in this Section. To the extent Tenant does not perform such remedial
work within a reasonable time after notice from Landlord, and if Landlord thereafter performs the same, Tenant shall reimburse
Landlord for any extra expenses actually incurred by Landlord by reason of faulty work done by Tenant or its contractors, or by
reason of delays caused by such work, or by reason of inadequate clean-up.
  
                                                                27


     17.9. Within sixty (60) days after final completion of any Alterations performed by Tenant with respect to the Premises, 
Tenant shall submit to Landlord documentation showing the amounts expended by Tenant with respect to such Alterations,
together with supporting documentation reasonably acceptable to Landlord.

     17.10. Tenant shall take, and shall cause its contractors to take, commercially reasonable steps to protect the Premises
during the performance of any Alterations, including covering or temporarily removing any window coverings so as to guard
against dust, debris or damage.

     17.11. Tenant shall require its contractors and subcontractors performing work on the Premises to name the Landlord
Parties and Lenders as additional insureds on their respective general liability insurance policies.

18. Repairs and Maintenance .
     18.1. Landlord shall repair and maintain in good condition the structural and exterior portions and Common Areas of the
Building and the Property, including roofing and covering materials; foundations; exterior walls; plumbing; fire sprinkler
systems (if any); heating, ventilating, air conditioning systems; elevators; and electrical systems installed or furnished by
Landlord consistent with other similar properties in the rental market in which the Building is located, and in full accordance
with Applicable Laws applicable to office and laboratory use generally, without regard for Tenant’s Alterations. The Common
Areas shall be maintained by Landlord in compliance with the ADA except to the extent such compliance would not be required
but for Tenant’s Alterations or its particular use of the Premises, as opposed to the Permitted Uses, generally. Landlord shall
maintain (or provide for the maintenance of) in a neat, attractive and first-class condition all signs, roadways, landscaped areas,
parking areas, sidewalks and entrances areas on the Property.

     18.2. Except for services of Landlord, if any, required by Section 18.1 , Tenant shall at Tenant’s sole cost and expense
maintain and keep the Premises and every part thereof in good condition and repair, excepting damage thereto from ordinary
wear and tear, and damage by casualty or condemnation (except to the extent Tenant is obligated to restore the same) excepted.
Tenant shall, upon the expiration or sooner termination of the Term, surrender the Premises to Landlord in as good a condition
as when received, excepting damage thereto from ordinary wear and tear, and damage by casualty or condemnation (except to
the extent Tenant is obligated to restore the same), and matters for which Tenant is not responsible; and shall, at Landlord’s
request and Tenant’s sole cost and expense, remove all telephone and data systems, wiring and equipment from the Premises,
and repair any damage to the Premises caused thereby. Landlord shall have no obligation to alter, remodel, improve, repair,
decorate or paint the Premises or any part thereof, other than as described in Exhibit B . Tenant shall be responsible, at its sole
cost and expense, for the cleaning of the Premises and Tenant’s removal of its trash, garbage and Hazardous Materials;
provided, however, that Tenant is encouraged to participate in the waste removal and recycling program in place at the
Property. Landlord shall provide a dumpster at the loading dock for Tenant’s use in the disposal of materials (other than
Hazardous Materials and other controlled substances).
  
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      18.3. Landlord shall not be liable for Claims arising out of any failure to make any repairs or to perform any maintenance
that is Landlord’s obligation pursuant to this Lease unless such failure shall persist for an unreasonable time after Tenant
provides Landlord with written notice of the need of such repairs or maintenance (or unless Landlord has actual knowledge of
the need therefor). Tenant waives its rights under Applicable Laws now or hereafter in effect to make repairs at Landlord’s
expense; however, in the event that Landlord fails to make a repair or perform maintenance that is Landlord’s obligation
pursuant to this Lease within applicable notice and cure periods set forth in Section 31.11, and such failure continues for ten 
pursuant to this Lease within applicable notice and cure periods set forth in Section 31.11, and such failure continues for ten 
(10) days after notice thereof to Landlord (with a copy to Landlord’s mortgagee) or such shorter period, if any, as may be
feasible in case of an emergency threatening life or property (such notice to expressly state in bold and prominent print
Tenant’s intention to exercise its rights under this Section), then Tenant, without being under any obligation to do so and
without thereby waiving such default, may remedy such default and perform such repair for the account and at the expense of
Landlord. All reasonable expenditures made by Tenant in connection therewith, including reasonable attorneys’ fees in
instituting, prosecuting or defending any action or proceeding, shall be paid to Tenant by Landlord within thirty (30) days after 
submission by Tenant to Landlord of a reasonably detailed invoice therefor. If Landlord fails to pay such costs to Tenant within
fifteen (15) days following notice from Tenant of such failure, then Tenant shall have the right to recover the same by an 
abatement of Base Rent and the Property Management Fee, provided that such abatement (and the accrual of any interest on
such amounts) shall cease at such time as and to the extent that payment is tendered to Tenant. Notwithstanding the foregoing,
if the amount of the abatement is more than 25% of the aggregate amount of Base Rent due in any month, then the amount
abated in any one month shall not exceed 25% of the Base Rent and the excess amount of the abatement shall be carried forward
with interest at the Default Rate. Tenant’s self-help rights under this paragraph shall be exercised by Tenant only (a) with 
respect to conditions actually existing within the Premises and (b) with respect to conditions that materially affect Tenant’s
ability to use and enjoy the Premises and to conduct Tenant’s operations therein. The provisions of this paragraph may not be
exercised by or on behalf of any subtenants. Any disputes regarding Tenant’s right to have undertaken any such remedy, the
amount of reimbursement claimed by Tenant, or the amount of abatement shall be resolved by arbitration as set forth below.

      The parties shall direct the Boston office of the AAA to appoint an arbitrator who shall have a minimum of ten (10) years’ 
experience in commercial real estate disputes and who shall not be affiliated with either Landlord or Tenant and has not worked
for either party or its affiliates at any time during the prior five (5) years. Both Landlord and Tenant shall have the opportunity 
to present evidence and outside consultants to the arbitrator.

     The arbitration shall be conducted in accordance with the expedited commercial arbitration rules of the AAA insofar as
such rules are not inconsistent with the provisions of this Lease (in which case the provisions of this Lease shall govern). The
cost of the arbitration (exclusive of each party’s witness and attorneys’ fees, which shall be paid by such party) shall be borne
equally by the parties. Any such arbitration shall be commenced within ten (10) days after demand (or, if later, appointment of 
the arbitrator).
  
                                                                  29


     Within ten (10) days after appointment, the arbitrator shall determine whether Tenant was entitled to exercise its self-help
rights and/or the amount of reimbursement to which Tenant is entitled. The arbitrator’s decision shall be final and binding on
the parties.

     18.4. If any excavation shall be made upon land adjacent to or under the Building, or shall be authorized to be made, then at
reasonable times and upon reasonable advance notice, Tenant shall afford to the person causing or authorized to cause such
excavation, license to enter the Premises for the purpose of performing such work as such person shall deem necessary or
desirable to preserve and protect the Building from injury or damage and to support the same by proper foundations, without
any claim for damages or liability against Landlord and without reducing or otherwise affecting Tenant’s obligations under this
Lease. Such work will be done at Landlord’s sole cost, and Landlord shall take such measures as are reasonably and
customarily required to avoid any adverse impacts on Tenant’s use and occupancy of the Premises.

    18.5. This Article relates to repairs and maintenance arising in the ordinary course of operation of the Building and the
Property. In the event of a casualty described in Article 24 , Article 24 shall apply in lieu of this Article. In the event of eminent
domain, Article 25 shall apply in lieu of this Article.

     18.6. Costs incurred by Landlord pursuant to this Article shall constitute Operating Expenses (unless otherwise limited or
excluded under Article 9).

19. Liens .
     19.1. Subject to the immediately succeeding sentence, Tenant shall keep the Premises, the Building and the Property free
from any liens arising out of work performed, materials furnished or obligations incurred by Tenant. Tenant further covenants
and agrees that any mechanic’s lien filed against the Premises, the Building or the Property for work claimed to have been done
for, materials claimed to have been furnished to, or obligations incurred by Tenant shall be discharged or bonded by Tenant
within fifteen (15) days after the filing thereof, at Tenant’s sole cost and expense.

    19.2. Should Tenant fail to discharge or bond against any lien of the nature described in Section 19.1 , Landlord may, at
Landlord’s election, pay such claim or post a bond or otherwise provide security to eliminate the lien as a claim against title, and
Tenant shall immediately reimburse Landlord for the costs thereof as Additional Rent. Tenant shall indemnify, save, defend (at
Landlord’s option and with counsel reasonably acceptable to Landlord) and hold the Landlord Indemnitees harmless from and
against any Claims arising from any such liens, including any administrative, court or other legal proceedings related to such
liens.

      19.3. In the event that Tenant leases or finances the acquisition of office equipment, furnishings or other personal property
of a removable nature utilized by Tenant in the operation of Tenant’s business, Tenant warrants that any Uniform Commercial
Code financing statement shall, upon its face or by exhibit thereto, indicate that such financing statement is applicable only to
removable personal property of Tenant located within the Premises. In no event shall the address of the Premises, the Building
or the Property be furnished on a financing statement without qualifying language as to applicability of the lien only to
removable personal property
  
                                                                  30


located in an identified suite leased by Tenant. Should any holder of a financing statement record or place of record a financing
statement that appears to constitute a lien against any interest of Landlord or against equipment that may be located other than
within an identified suite leased by Tenant, Tenant shall, within ten (10) days after filing such financing statement, cause (a) a 
copy of the Lender security agreement or other documents to which the financing statement pertains to be furnished to
Landlord to facilitate Landlord’s ability to demonstrate that the lien of such financing statement is not applicable to Landlord’s
interest and (b) Tenant’s Lender to amend such financing statement and any other documents of record to clarify that any liens
imposed thereby are not applicable to any interest of Landlord in the Premises, the Building or the Property. Landlord will, on
request by Tenant, execute and deliver any reasonable waiver or subordination of Landlord’s lien that may be required in
connection with any such financing, provided the same does not amend the provisions of this Lease and is reasonably
acceptable to Landlord. Tenant shall be responsible for, and shall reimburse Landlord for, all reasonable attorneys’ fees incurred
by Landlord in connection with any such request.

20. Estoppel Certificate . (a) Tenant shall, within ten (10) business days of receipt of written notice from Landlord, execute, 
acknowledge and deliver a statement in writing substantially in the form attached to this Lease as Exhibit I , or on any other form
reasonably requested by a proposed Lender or purchaser, (a) certifying that this Lease is unmodified and in full force and effect 
(or, if modified, stating the nature of such modification and certifying that this Lease as so modified is in full force and effect)
and the dates to which rental and other charges are paid in advance, if any, (b) acknowledging that there are not, to Tenant’s
knowledge, any uncured defaults on the part of Landlord hereunder, or specifying such defaults if any are claimed, and
(c) setting forth such further factual information with respect to this Lease or the Premises as may be reasonably requested 
thereon. Any such statement may be relied upon by any prospective purchaser or encumbrancer of all or any portion of the real
property of which the Premises are a part. Tenant’s failure to deliver such statement within such the prescribed time, if such
failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which notice shall state, in bold 
and prominent print, that failure to reply shall result in a Default under this Section 21(a)), shall, at Landlord’s option, constitute
a Default (as defined below) under this Lease and, in any event, shall be binding upon Tenant that this Lease is in full force and
effect and without modification except as may be represented by Landlord in any certificate prepared by Landlord and delivered
to Tenant for execution. However, no such certificate shall have the effect of amending this Lease, and in the case of any
conflict between this Lease and any certificate, this Lease shall prevail.

           (b) Landlord shall, within ten (10) business days of receipt of written notice from Tenant, execute, acknowledge and 
deliver a statement in writing (a) certifying that this Lease is unmodified and in full force and effect (or, if modified, stating the 
nature of such modification and certifying that this Lease as so modified is in full force and effect) and the dates to which rental
and other charges are paid in advance, if any, (b) acknowledging that there are not, to Landlord’s knowledge, any uncured
defaults on the part of Tenant hereunder, or specifying such defaults if any are claimed, and (c) setting forth such further 
factual information with respect to this Lease or the Premises as may be reasonably requested thereon. However, no such
certificate shall have the effect of amending this Lease, and in the case of any conflict between this Lease and any certificate,
this Lease shall prevail.
  
                                                                  31


21. Hazardous Materials .
     21.1. Tenant shall not cause or permit any Hazardous Materials (as defined below) to be brought upon, kept or used in or
      21.1. Tenant shall not cause or permit any Hazardous Materials (as defined below) to be brought upon, kept or used in or
about the Premises, the Building or the Property in violation of Applicable Laws by Tenant or its employees, agents,
contractors or invitees. If Tenant breaches such obligation, or if the presence of Hazardous Materials as a result of such a
breach results in contamination of the Property, any portion thereof, or any adjacent property, or if contamination of the
Premises otherwise occurs during the Term or any extension or renewal hereof or holding over hereunder (other than if such
contamination results from migration of Hazardous Materials from outside the Premises not caused by Tenant or its employees,
agents, contractors or invitees), then Tenant shall indemnify, save, defend (at Landlord’s option and with counsel reasonably
acceptable to Landlord) and hold the Landlord Indemnitees harmless from and against any and all Claims that arise during or
after the Term as a result of such breach or contamination. This indemnification by Tenant includes costs incurred in
connection with any investigation of site conditions or any clean-up, remedial, removal or restoration work required by any
Governmental Authority because of Hazardous Materials present in the air, soil or groundwater above, on or under or about the
Property. Without limiting the foregoing, if the presence of any Hazardous Materials in, on, under or about the Property, any
portion thereof or any adjacent property caused or permitted by Tenant results in any contamination of the Property, any
portion thereof or any adjacent property, then Tenant shall promptly take all actions at its sole cost and expense as are
necessary to return the Property, any portion thereof or any adjacent property to its respective condition existing prior to the
time of such contamination; provided that Landlord’s written approval of such action shall first be obtained, which approval
Landlord shall not unreasonably withhold; and provided , further, that it shall be reasonable for Landlord to withhold its
consent if such actions could have a material adverse long-term or short-term effect on the Property, any portion thereof or any
adjacent property. Notwithstanding any provision of this Lease to the contrary, Tenant shall in no event have any liability (by
way of indemnification or otherwise) for removal or remediation of any Hazardous Materials from the Premises or the Property to
the extent (i) of any condition existing in, on or under the Premises or the Property, as the case may be, on the Term 
Commencement Date, (ii) related to Hazardous Materials that migrate to the Premises following the Term Commencement Date 
from some other part of the Building or Property other than as a result of the acts or omissions of Tenant or any Tenant Party,
or (iii) placed or release in or on the Premises following the Term Commencement Date by Landlord or Landlord’s agents,
contractors and employees.

      21.2. Landlord acknowledges that it is not the intent of this Article to prohibit Tenant from operating its business for the
Permitted Use. Tenant may operate its business according to the custom of Tenant’s industry so long as the use or presence of
Hazardous Materials is strictly and properly monitored in accordance with Applicable Laws. As a material inducement to
Landlord to allow Tenant to use Hazardous Materials in connection with its business, Tenant agrees to deliver to Landlord
(a) so-called MSDS sheets identifying each type of Hazardous Material to be present at the Premises that is subject to
regulation under any environmental Applicable Laws, (b) a list of any and all approvals or permits from Governmental 
Authorities required in connection with the presence of such Hazardous Material at the Premises and (c) correct and complete 
copies of (i) written notices of violations of Applicable Laws actually received by Tenant related to Hazardous Materials at the 
Premises and (ii) plans relating to the installation of any storage tanks to be installed in, on, under or about the Property 
( provided that
  
                                                                32


installation of storage tanks shall only be permitted after Landlord has given Tenant its written consent to do so, which consent
Landlord may withhold in its reasonable discretion with respect to above-ground storage tanks, and its sole and absolute
discretion with respect to underground storage tanks, if any) and closure plans or any other documents required by any and all
Governmental Authorities for any storage tanks installed in, on, under or about the Property for the closure of any such storage
tanks (collectively, “ Hazardous Materials Documents ”). Tenant shall deliver to Landlord updated Hazardous Materials
Documents (l) no later than thirty (30) days prior to the initial occupancy of any portion of the Premises or the initial placement 
of equipment anywhere at the Property, (m) if there are any changes to the Hazardous Materials Documents, annually thereafter 
no later than December 31 of each year, and (n) thirty (30) days prior to the initiation by Tenant of any Alterations or changes in 
Tenant’s business that involve any material increase in the types or amounts of Hazardous Materials. For each type of
Hazardous Material listed, the Hazardous Materials Documents shall include (t) the chemical name, (u) the material state (e.g., 
solid, liquid, gas or cryogen), (v) the concentration, (w) the storage amount and storage condition (e.g., in cabinets or not in 
cabinets), (x) the use amount and use condition (e.g., open use or closed use), (y) the location (e.g., room number or other 
identification) and (z) if known, the chemical abstract service number. Notwithstanding anything in this Section to the contrary, 
Tenant shall not be required to provide Landlord with any Hazardous Materials Documents containing information of a
proprietary nature, which Hazardous Materials Documents, in and of themselves, do not contain a reference to any Hazardous
Materials or activities related to Hazardous Materials. Landlord may, at Landlord’s expense, cause the Hazardous Materials
Documents to be reviewed by a person or firm qualified to analyze Hazardous Materials to confirm compliance with the
provisions of this Lease and with Applicable Laws. In the event that a review of the Hazardous Materials Documents indicates
non-compliance with this Lease or Applicable Laws, Tenant shall, at its expense, diligently take steps to bring its storage and
use of Hazardous Materials into compliance. Notwithstanding anything to the contrary herein, in no event shall Tenant
generate, produce, bring upon, use, store or treat Hazardous Materials with a risk category higher than Biosafety Level 2 as 
generate, produce, bring upon, use, store or treat Hazardous Materials with a risk category higher than Biosafety Level 2 as 
established by the Department of Health and Human Services (“ DHHS ”) and as further described in the DHHS publication
Biosafety in Microbiological and Biomedical Laboratories (5th Edition) (as it may be or may have been further revised, the “ 
BMBL ”) or such nationally recognized new or replacement standards as may be reasonably selected by Landlord if applicable
to similar facilities in the City of Cambridge).

     21.3. Notwithstanding the provisions of Sections 21.1 , 21.2 or 21.9 , if any proposed transferee, assignee or sublessee of
Tenant is then subject to an outstanding material enforcement order issued by any Governmental Authority in connection with
the use, disposal or storage of Hazardous Materials, then it shall not be unreasonable for Landlord to withhold its consent to
any proposed transfer, assignment or subletting (with respect to any such matter involving a proposed transferee, assignee or
sublessee).

     21.4. At any time, and from time to time, prior to the expiration of the Term, Landlord shall have the right to conduct
appropriate tests of the Property or any portion thereof to demonstrate that Hazardous Materials are present or that
contamination has occurred due to the acts or omissions of Tenant or Tenant’s employees, agents, contractors or invitees
(provided that such tests shall be conducted in a manner that does not unreasonably interrupt or interfere with Tenant’s use of
the Premises for the Permitted Use). Tenant shall pay all reasonable costs of such tests if such tests reveal that Hazardous
Materials exist at the Property in violation of this Lease.
  
                                                                33


     21.5. If underground or other storage tanks storing Hazardous Materials installed or utilized by Tenant are located on the
Premises, or are hereafter placed on the Premises by Tenant (or by any other party, if such storage tanks are utilized by Tenant),
then Tenant shall monitor the storage tanks, maintain appropriate records, implement reporting procedures, properly close any
underground storage tanks, and take or cause to be taken all other steps necessary or required under the Applicable Laws.
Tenant shall have no responsibility or liability for underground or other storage tanks installed by anyone other than Tenant
unless Tenant utilizes such tanks, in which case Tenant’s responsibility for such tanks shall be as set forth in this Section.

     21.6. Tenant shall promptly report to Landlord any actual or suspected presence of mold or water intrusion in the Premises.

     21.7. Tenant’s obligations under this Article shall survive the expiration or earlier termination of this Lease. During any
period of time needed by Tenant or Landlord after the termination of this Lease to complete the removal from the Premises of
any such Hazardous Materials, Tenant shall be deemed a holdover tenant and subject to the provisions of Article 27 below.

     21.8. As used herein, the term “ Hazardous Material ” means, but shall not be limited to, any hazardous substances,
hazardous waste, environmental, biological, chemical, radioactive substances, oil, petroleum products and any waste or
substance, which because of its quantitative concentration, chemical, biological, radioactive, flammable, explosive, infectious or
other characteristics, constitutes or may reasonably be expected to constitute or contribute to a danger or hazard to public
health, safety or welfare or to the environment, including without limitation any asbestos (whether or not friable) and any
asbestos-containing materials, lead paint, waste oils, solvents and chlorinated oils, polychlorinated biphenyls (PCBs), toxic
metals, etchants, pickling and plating wastes, explosives, reactive metals and compounds, pesticides, herbicides, radon gas,
urea formaldehyde foam insulation and chemical, biological and radioactive wastes, or any other similar materials that are
regulated by any Governmental Authority.

      21.9. Notwithstanding anything to the contrary in this Lease, Landlord shall have sole control over the equitable allocation
of fire control areas (as defined in the Uniform Building Code as adopted by the city or municipality(ies) in which the Property is
located (the “ UBC ”)) within the Property for the storage of Hazardous Materials; provided that Tenant shall have the
appurtenant right to use its pro-rata share of such fire control areas made available to tenants on any floor of the Premises
(determined on a floor-by-floor basis based on the ratio of the rentable square footage of the Premises on such floor to the total
rentable square footage of leasable area on such floor as reasonably determined by Landlord on a consistent basis), other than
the first floor of the Building if and to the extent the Premises includes any portion of such floor. Notwithstanding anything to
the contrary in this Lease, the quantity of Hazardous Materials allowed by this Section 21.9 is specific to Tenant and shall not
run with the Lease in the event of a Transfer (as defined in Article 29 ). In the event of a Transfer, if the use of
  
                                                                34


Hazardous Materials by such new tenant (“ New Tenant ”) is such that New Tenant utilizes fire control areas in the Building in
excess of New Tenant’s Pro Rata Share of the Building, then New Tenant shall, at its sole cost and expense and upon
excess of New Tenant’s Pro Rata Share of the Building, then New Tenant shall, at its sole cost and expense and upon
Landlord’s written request, establish and maintain a separate area of the Premises classified by the UBC as an “H” occupancy
area for the use and storage of Hazardous Materials, or take such other action as is necessary to ensure that its share of the fire
control areas of the Building is not greater than New Tenant’s Pro Rata Share of the Building.

22. Odors and Exhaust . Tenant acknowledges that Landlord would not enter into this Lease with Tenant unless Tenant assured
Landlord that under no circumstances will any other occupants of the Building or the Property (including persons legally
present in any outdoor areas of the Property) be subjected to odors or fumes (whether or not noxious), and that the Building
and the Property will not be damaged by any exhaust, in each case from Tenant’s operations. Landlord and Tenant therefore
agree as follows (and Landlord agrees that it will use commercially reasonable efforts to include substantially similar provisions
regarding odors and exhaust in all lease agreements with other office and/or laboratory tenants or occupants of the Building):

     22.1. Tenant shall not cause or permit (or conduct any activities that would cause) any release of any odors or fumes of
any kind inconsistent with typical first-class office and laboratory use from the Premises.

     22.2. If the Building has a ventilation system that, in Landlord’s judgment, is adequate, suitable, and appropriate to vent
the Premises in a manner that does not release odors affecting any indoor or outdoor part of the Property, Tenant shall vent the
Premises through such system. If Landlord at any time determines that any existing ventilation system is inadequate, or if no
ventilation system exists, Tenant shall in compliance with Applicable Laws vent all fumes and odors from the Premises (and
remove odors from Tenant’s exhaust stream) as Landlord reasonably requires. The placement and configuration of all
ventilation exhaust pipes, louvers and other equipment shall be subject to Landlord’s approval. Tenant acknowledges
Landlord’s legitimate desire to maintain the Property (indoor and outdoor areas) in an odor-free manner, and Landlord may
require Tenant to abate and remove all odors in a manner that goes beyond the requirements of Applicable Laws.

     22.3. Tenant shall, at Tenant’s sole cost and expense, provide commercially reasonable levels of odor eliminators and other
devices (such as filters, air cleaners, scrubbers and whatever other equipment may in Landlord’s judgment be reasonably
necessary or appropriate from time to time) to completely remove, eliminate and abate any odors, fumes or other substances in
Tenant’s exhaust stream that emanate from Tenant’s operations in the Premises. Any work Tenant performs under this Section
shall constitute Alterations.

     22.4. Tenant’s responsibility to remove, eliminate and abate odors, fumes and exhaust caused by operations conducted by,
through or under Tenant shall continue throughout the Term. Landlord’s approval of any Alterations shall not preclude
Landlord from requiring additional measures to eliminate odors, fumes and other adverse impacts of Tenant’s exhaust stream (as
Landlord may designate in Landlord’s reasonable discretion). To the extent reasonably necessary to control odors or fumes
caused by operations conducted by, through or under Tenant, Tenant shall install additional equipment as Landlord reasonably
requires from time to time under the preceding sentence. Such installations shall constitute Alterations.
  
                                                                 35


     22.5. If Tenant fails to install satisfactory odor control equipment within thirty (30) days after Landlord’s demand made at
any time (which may include effective temporary measures so long as permanent measures are taken within thirty (30) days 
thereafter), then Landlord may, without limiting Landlord’s other rights and remedies, require Tenant to cease and suspend any
operations in the Premises that, in Landlord’s determination, cause odors, fumes or exhaust. For example, if Landlord determines
that Tenant’s production of a certain type of product causes odors, fumes or exhaust, and Tenant does not install satisfactory
odor control equipment within thirty (30) days after Landlord’s request, then Landlord may require Tenant to stop producing
such type of product in the Premises unless and until Tenant has installed odor control equipment satisfactory to Landlord.

     22.6. In the event that Tenant installs or maintains any small animal facilities in connection with its laboratory operations in
the Premises, Tenant shall construct and maintain a vacuum-enabled disposal facility for bedding waste and any other noxious
wastes (or such other disposal system reasonably acceptable to Landlord that satisfactorily disposes of such wastes and
controls odors). In no event may any such animal facilities exceed 25,000 square feet of Rentable Area within the Premises.

23. Insurance; Waiver of Subrogation .
     23.1. Landlord shall maintain property insurance for the Building and the Property in amounts equal to full replacement
cost (exclusive of the costs of excavation, foundations and footings, and without reference to depreciation taken by Landlord
upon its books or tax returns), providing protection against any peril generally included within the classification “Special Form,” 
together with insurance against sprinkler damage (if applicable), vandalism and malicious mischief and boiler and machinery
coverage. Landlord, subject to availability thereof, shall further insure, if Landlord deems it appropriate, coverage against flood,
environmental hazard, earthquake, loss or failure of building equipment, rental loss during the period of repairs or rebuilding,
workmen’s compensation insurance and fidelity bonds for employees employed to perform services and may carry such other
workmen’s compensation insurance and fidelity bonds for employees employed to perform services and may carry such other
insurance coverages, and additional amounts, as are prudent in Landlord’s reasonable determination or are required by
mortgagees from time to time.

      23.2. In addition, Landlord shall carry commercial general liability insurance with a combined single limit of not less than
Five Million Dollars ($5,000,000) for death or bodily injury, or property damage with respect to the Property, to be written on an
occurrence basis. Such insurance required to be carried by Landlord shall be with companies authorized to do business in the
state in which the Property is located and having a rating of not less than policyholder rating of “A-” and financial category
rating of at least Class X in “Best’s Insurance Guide.” 

     23.3. Tenant shall, at its own cost and expense, procure and maintain in effect, beginning on the Term Commencement
Date, and continuing throughout the Term (and occupancy by Tenant, if any, after termination of this Lease) commercial
general liability insurance with limits of not less than Five Million Dollars $5,000,000) per occurrence for death or bodily injury
and for property damage with respect to the Premises (including $100,000 fire legal liability (each loss)).
  
                                                                 36


      23.4. The insurance required to be purchased and maintained by Tenant pursuant to this Lease shall name Landlord, BMR-
PR II LLC, BioMed Realty, L.P., BioMed Realty Trust, Inc., The Prudential Insurance Company of America, BioMed Realty LLC,
and their respective officers, directors, employees, agents, general partners, members, subsidiaries, affiliates and Lenders (“ 
Landlord Parties ”) as additional insureds. Such insurance shall be with companies authorized to do business in the state in
which the Property is located and having a rating of not less than policyholder rating of “A-” and financial category rating of at
least Class X in “Best’s Insurance Guide.” No such additional insured coverage shall be required to protect or insure against
loss arising from the negligence or wrongful act or omissions of an additional insured. Tenant shall obtain for Landlord from the
insurance companies or cause the insurance companies to furnish certificates of coverage to Landlord. No such policy shall be
cancelable or subject to material reduction of coverage except after thirty (30) days’ prior written notice to Landlord (except in
the event of non-payment of premium, in which case ten (10) days written notice shall be given). All such policies shall be 
written as primary policies, not contributing with and not in excess of the coverage that Landlord may carry. Tenant’s policy
may be a “blanket policy” that specifically provides that the amount of insurance shall not be prejudiced by other losses
covered by the policy. Tenant shall, no later than ten (10) days following the expiration of such policies, furnish evidence 
reasonably acceptable to Landlord of Tenant’s procurement of replacement insurance. Tenant agrees that if Tenant does not
take out and maintain such insurance, Landlord may (but shall not be required to) procure such insurance on Tenant’s behalf
and at its cost to be paid by Tenant as Additional Rent.

     23.5. Except for matters arising from the negligence or willful misconduct of Landlord or its agents, contractors and
employees (and then subject to Section 23.7), Tenant assumes the risk of damage to any fixtures, goods, inventory, 
merchandise, equipment and leasehold improvements, and Landlord shall not be liable for injury to Tenant’s business or any
loss of income therefrom, relative to such damage, all as more particularly set forth within this Lease. Tenant shall, at Tenant’s
sole cost and expense, carry such insurance as Tenant desires for Tenant’s protection with respect to personal property of
Tenant or business interruption.

     23.6. In each instance where insurance is to name Landlord Parties as additional insureds, Tenant shall, upon Landlord’s
written request, also designate and furnish certificates evidencing such Landlord Parties as additional insureds to (a) any 
Lender of Landlord holding a security interest in the Building or the Property, (b) the landlord under any lease whereunder 
Landlord is a tenant of the Property if the interest of Landlord is or shall become that of a tenant under a ground lease rather
than that of a fee owner and (c) any management company retained by Landlord to manage the Property. 

     23.7. Landlord and Tenant each hereby waive any and all rights of recovery against the other or against the officers,
directors, employees, agents, general partners, members, subsidiaries, affiliates and Lenders of the other on account of loss or
damage occasioned by such waiving party or its property or the property of others under such waiving party’s control, in each
case to the extent that such loss or damage is insured (or required under this Lease to be insured) against under any fire and
extended coverage insurance policy that either Landlord or Tenant
  
                                                                 37


may have in force at the time of such loss or damage. Such waivers shall continue so long as their respective insurers so permit.
Any termination of such a waiver shall be by written notice to the other party, containing a description of the circumstances
hereinafter set forth in this Section. Landlord and Tenant, upon obtaining the policies of insurance required or permitted under
this Lease, shall give notice to the insurance carrier or carriers that the foregoing mutual waiver of subrogation is contained in
this Lease, shall give notice to the insurance carrier or carriers that the foregoing mutual waiver of subrogation is contained in
this Lease. If such policies shall not be generally obtainable from reputable insurers with such waiver or shall be so obtainable
only at a premium over that chargeable without such waiver, then the party seeking such policy shall notify the other of such
conditions, and the party so notified shall have ten (10) days thereafter to either (a) procure such insurance with companies 
reasonably satisfactory to the other party or (b) agree to pay such additional premium (in Tenant’s case, in the proportion that
the area of the Premises bears to the insured area). If the parties do not accomplish either (a) or (b), then this Section shall have 
no effect during such time as such policies shall not be obtainable or the party in whose favor a waiver of subrogation is
desired refuses to pay the additional premium. If such policies shall at any time be generally unobtainable from reputable
insurers, but shall be subsequently obtainable, then neither party shall be subsequently liable for a failure to obtain such
insurance until a reasonable time after notification thereof by the other party. If the release of either Landlord or Tenant, as set
forth in the first sentence of this Section, shall contravene Applicable Laws, then the liability of the party in question shall be
deemed not released but shall be secondary to the other party’s insurer.

     23.8. Landlord may require insurance policy limits required under this Lease to be raised from time to time to conform with
reasonable requirements of Landlord’s Lender or to bring coverage limits to reasonable levels then being required of other
similar office and laboratory tenants within Kendall Square, generally.

     23.9. Any costs incurred by Landlord pursuant to this Article shall constitute a portion of Operating Expenses to the extent
not otherwise expressly excluded pursuant to the provisions of Section 9.1(c). 

24. Damage or Destruction .
      24.1. In the event of a partial destruction of (a) the Premises or (b) Common Areas of the Building or the Property ((a) and 
(b) together, the “ Affected Areas ”) by fire or other perils covered by special form insurance not exceeding twenty-five percent
(25%) of the full insurable value thereof, and provided that the damage thereto is such that the Affected Areas may be repaired,
reconstructed or restored within a period of one (1) year from the adjustment of such casualty loss with the insurer, and 
Landlord shall receive insurance proceeds sufficient to cover the cost of such repairs, reconstruction and restoration (except for
any commercially reasonable deductible amount provided by Landlord’s policy, which deductible amount, if paid by Landlord,
shall constitute an Operating Expense, and provided that Landlord shall have complied with the requirements of Section 23.1), 
then Landlord shall commence and proceed diligently with the work of repair, reconstruction and restoration of the Affected
Areas and this Lease shall continue in full force and effect. If Landlord does not receive insurance proceeds sufficient to cover
the cost of such repairs, reconstruction and restoration, despite Landlord’s diligent and commercially reasonable efforts, and
neither Landlord nor any Mortgagee has commenced such restoration within three (3) months following 
  
                                                                  38


adjustment of such casualty loss with the insurer, then Tenant may, until any such restoration commences, terminate this Lease
by giving at least thirty (30) days’ prior written notice thereof to Landlord and such termination shall be effective on the date
specified if such replacement has not then commenced.

       24.2. In the event of any damage to or destruction of the Building or the Property other than as described in Section 24.1 ,
Landlord may elect to repair, reconstruct and restore the Building or the Property, as applicable, in which case this Lease shall
continue in full force and effect. If Landlord elects not to repair, reconstruct and restore the Building or the Property, as
applicable, in accordance with Section 24.3, below, then this Lease shall terminate as of the date of such damage or destruction. 
In the event of any damage or destruction (regardless of whether such damage is governed by Section 24.1 or this Section), if
(a) in Landlord’s determination as set forth in the Damage Repair Estimate (as defined below), the Affected Areas cannot be
repaired, reconstructed or restored within twelve (12) months after the date that repairs would commence (provided such 
Damage Repair Estimate is provided to Tenant within 60 days following the date of such damage or destruction), or (b) subject 
to Section 24.6 , the Affected Areas are not actually repaired, reconstructed and restored within the longer of (I) twelve 
(12) months after the date that repairs were to commence as estimated in the Damage Repair Estimate or (II) the period estimated 
for repair as set forth in the Damage Repair Estimate, then Tenant shall have the right to terminate this Lease, effective as of the
date of such damage or destruction, by delivering to Landlord its written notice of termination (a “ Termination Notice ”)
(y) with respect to Subsection 24.2(a) , no later than fifteen (15) days after Landlord delivers to Tenant Landlord’s Damage
Repair Estimate and (z) with respect to Subsection 24.2(b) , no later than fifteen (15) days after such period (as the same may be 
extended pursuant to Section 24.6 ) expires. If Tenant provides Landlord with a Termination Notice pursuant to Subsection 24.2
(z) , Landlord shall have an additional thirty (30) days after receipt of such Termination Notice to complete the repair, 
reconstruction and restoration. If Landlord does not complete such repair, reconstruction and restoration within such thirty
(30) day period, then Tenant may terminate this Lease by giving Landlord written notice within two (2) business days after the 
expiration of such thirty (30) day period. If Landlord does complete such repair, reconstruction and restoration within such 
thirty (30) day period, then this Lease shall continue in full force and effect. If Landlord does not so give a notice of its election 
not to repair, then Landlord shall be deemed to have elected to repair the Property and Premises as aforesaid.
not to repair, then Landlord shall be deemed to have elected to repair the Property and Premises as aforesaid.

     24.3. As soon as reasonably practicable, but in any event within sixty (60) days following the date of damage or 
destruction, Landlord shall notify Tenant of Landlord’s good faith estimate of the period of time in which the repairs,
reconstruction and restoration will be completed (the “ Damage Repair Estimate ”), which estimate shall be based upon the
opinion of a contractor reasonably selected by Landlord and experienced in comparable repair, reconstruction and restoration of
similar buildings. Additionally, Landlord shall give written notice to Tenant within sixty (60) days following the date of damage 
or destruction of its election not to repair, reconstruct or restore the Building or the Property, as applicable.

      24.4. Upon any termination of this Lease under any of the provisions of this Article, the parties shall be released thereby
without further obligation to the other from the date possession of the Premises is surrendered to Landlord, except with regard
to (a) items occurring prior to the damage or destruction and (b) provisions of this Lease that, by their express terms, survive 
the expiration or earlier termination hereof.
  
                                                                 39


      24.5. In the event of repair, reconstruction and restoration as provided in this Article, all Rent to be paid by Tenant under
this Lease shall be abated proportionately based on the extent to which Tenant’s use of the Premises is impaired during the
period of such repair, reconstruction or restoration (and the Property Management Fee shall be reduced based on such
reduction in Base Rent, if any), unless Landlord provides Tenant with other space during the period of repair, reconstruction
and restoration that, in Tenant’s reasonable opinion, is suitable for the temporary conduct of Tenant’s office and/or laboratory
operations. Tenant acknowledges that, given such abatement, Tenant will not have any claim against its own insurer to recover
rent that would otherwise have been payable during the period of such abatement.

     24.6. Notwithstanding anything to the contrary contained in this Article, should Landlord be delayed or prevented from
completing the repair, reconstruction or restoration of the damage or destruction to the Premises after the occurrence of such
damage or destruction by matters described in Section 41.6 of this Lease or delays caused by Tenant or its employees, agents, 
contractors or invitees, then the time for Landlord to commence or complete repairs, reconstruction and restoration shall be
extended on a day-for-day basis.

      24.7. If Landlord is obligated to or elects to repair, reconstruct or restore as herein provided, then Landlord shall be
obligated to make such repairs, reconstruction or restoration only with regard to (a) those portions of the Premises that were 
originally provided at Landlord’s expense (i.e. excluding Alterations, other than to the extent funded by the TI Allowance) and
(b) the Common Area portion of the Affected Areas. The repairs, reconstruction or restoration of improvements not originally 
provided by Landlord or at Landlord’s expense shall be the obligation of Tenant. Tenant alone shall be entitled to settle, adjust
and receive the proceeds of any insurance policies held by Tenant, and to use the proceeds thereof as Tenant deems
appropriate for the restoration of Tenant’s Alterations. In the event Tenant has elected to upgrade certain improvements from
the Building Standard, Landlord shall, upon the need for replacement due to an insured loss, provide only the Building
Standard, unless Tenant again elects to upgrade such improvements and pay any incremental costs related thereto, except to
the extent that excess insurance proceeds, if received, are adequate to provide such upgrades, in addition to providing for basic
repairs, reconstruction and restoration of the Premises, the Building and the Property.

     24.8. Notwithstanding anything to the contrary contained in this Article, Landlord shall not have any obligation
whatsoever to repair, reconstruct or restore the Premises if the damage resulting from any casualty covered under this Article
occurs during the last twelve (12) months of the Term or any extension thereof, or to the extent that insurance proceeds are not 
available therefor.

    24.9. Landlord’s obligation, should it elect or be obligated to repair, reconstruct or restore, shall be limited to the Affected
Areas. Tenant shall, at its expense, replace or fully repair all of Tenant’s personal property and any Alterations installed by
Tenant existing at the time of such damage or destruction. If Affected Areas are to be repaired, reconstructed or restored in
  
                                                                 40


accordance with the foregoing, Landlord shall make available to Tenant any portion of insurance proceeds it receives that are
allocable to the Alterations constructed by Tenant pursuant to this Lease; provided Tenant is not then in monetary default of
which Tenant shall have received written notice in accordance with this Lease or otherwise in Default under this Lease, and
subject to the reasonable requirements of any Lender of Landlord as to the method of disbursement of such proceeds.

25. Eminent Domain .
     25.1. In the event (a) the whole of all Affected Areas or (b) such part thereof as shall substantially interfere (in Tenant’s
reasonable determination, made in good faith) with Tenant’s reasonable, efficient and beneficial use and occupancy of all or a
substantial portion of the Premises for the Permitted Use shall be taken for any public or quasi-public purpose by any lawful
power or authority by exercise of the right of appropriation, condemnation or eminent domain, or sold to prevent such taking,
Tenant or Landlord may terminate this Lease effective as of the date possession is required to be surrendered to such authority,
except with regard to (y) items occurring prior to the taking and (z) provisions of this Lease that, by their express terms, survive 
the expiration or earlier termination hereof.

     25.2. In the event of a partial taking of (a) the Building or the Property or (b) drives, walkways or parking areas serving the 
Building or the Property for any public or quasi-public purpose by any lawful power or authority by exercise of right of
appropriation, condemnation, or eminent domain, or sold to prevent such taking, then, without regard to whether any portion of
the Premises occupied by Tenant was so taken, Landlord may elect to terminate this Lease (except with regard to (y) items 
occurring prior to the taking and (z) provisions of this Lease that, by their express terms, survive the expiration or earlier 
termination hereof) as of such taking if such taking is, in Landlord’s sole opinion, of a material nature such as to make it
uneconomical to continue use of the unappropriated portion for purposes of renting office or laboratory space.
Notwithstanding the foregoing, Landlord may only exercise its option to terminate this Lease as described in this Section 25.2 if 
Landlord also terminates the leases of tenants similarly affected by such taking.

     25.3. Tenant shall be entitled to any award that is specifically awarded as compensation for (a) the taking of Tenant’s
personal property, trade fixtures and equipment that was installed at Tenant’s expense and (b) the costs of Tenant moving to a 
new location. Except as set forth in the previous sentence, any award for such taking shall be the property of Landlord.

     25.4. If, upon any taking of the nature described in this Article, this Lease continues in effect, then Landlord shall promptly
proceed to restore the Affected Areas to substantially their same condition prior to such partial taking. To the extent such
restoration is infeasible, as determined by Landlord in its reasonable discretion, the Rent shall be decreased proportionately to
reflect the loss of any portion of the Premises no longer available to Tenant (and the Property Management Fee shall be
reduced to reflect any decrease in Base Rent resulting therefrom).
  
                                                                  41


26. Surrender .
      26.1. At least 30 days prior to Tenant’s surrender of possession of any part of the Premises, Tenant shall provide Landlord
with (a) a facility decommissioning and Hazardous Materials closure plan for the Premises (“ Exit Survey ”) prepared by an
independent third party reasonably acceptable to Landlord, (b) written evidence of all appropriate governmental releases 
obtained by Tenant in accordance with Applicable Laws, including laws pertaining to the surrender of the Premises, and
(c) proof that the Premises have been decommissioned in accordance with American National Standards Institute (“ ANSI ”)
Publication Z9.11-2008 (entitled “Laboratory Decommissioning”) or any successor standards published by ANSI or any
successor organization (or, if ANSI and its successors no longer exist, a similar entity publishing similar standards). In addition,
Tenant agrees to remain responsible after the surrender of the Premises for the remediation of any recognized environmental
conditions set forth in the Exit Survey and compliance with any recommendations set forth in the Exit Survey. Tenant’s
obligations under this Section shall survive the expiration or earlier termination of this Lease.

     26.2. No surrender of possession of any part of the Premises shall release Tenant from any of its obligations hereunder,
unless such surrender is accepted in writing by Landlord.

     26.3. The voluntary or other surrender of this Lease by Tenant shall not effect a merger with Landlord’s fee title or
leasehold interest in the Premises, the Building or the Property, unless Landlord consents in writing, and shall, at Landlord’s
option, operate as an assignment to Landlord of any or all subleases.

     26.4. The voluntary or other surrender of any ground or other underlying lease that now exists or may hereafter be
executed affecting the Building or the Property, or a mutual cancellation thereof or of Landlord’s interest therein by Landlord
and its lessor shall not effect a merger with Landlord’s fee title or leasehold interest in the Premises, the Building or the Property
and shall, at the option of the successor to Landlord’s interest in the Building or the Property, as applicable, operate as an
assignment of this Lease.

27. Holding Over .
    27.1. If, with Landlord’s prior written consent, Tenant holds possession of all or any part of the Premises after the Term,
Tenant shall become a tenant from month to month after the expiration or earlier termination of the Term, and in such case
Tenant shall continue to pay (a) Base Rent in accordance with Article 7 , as adjusted in accordance with Article 8 , and (b) any 
Tenant shall continue to pay (a) Base Rent in accordance with Article 7 , as adjusted in accordance with Article 8 , and (b) any 
amounts for which Tenant would otherwise be liable under this Lease if the Lease were still in effect, including payments for
Tenant’s Share of Operating Expenses. Any such month-to-month tenancy shall be subject to every other term, covenant and
agreement contained herein.

      27.2. Notwithstanding the foregoing, if Tenant remains in possession of the Premises after the expiration or earlier
termination of the Term without Landlord’s prior written consent, (a) Tenant shall become a tenant at sufferance subject to the 
terms and conditions of this Lease, except that the monthly rent shall be equal to one hundred fifty percent (150%) of the Rent 
in effect during the last thirty (30) days of the Term, and (b) Tenant shall be liable to Landlord for any and all damages suffered 
by Landlord as a result of the length of such holdover that exceeds thirty (30) days, including any lost rent or consequential, 
special and indirect damages.
  
                                                                  42


    27.3. Acceptance by Landlord of Rent after the expiration or earlier termination of the Term shall not result in an extension,
renewal or reinstatement of this Lease.

     27.4. The foregoing provisions of this Article are in addition to and do not affect Landlord’s right of reentry or any other
rights of Landlord hereunder or as otherwise provided by Applicable Laws.

28. Indemnification and Exculpation .
      28.1. Except to the extent any matter arises from or as a result of the negligent or willful and wrongful act or omission of
Landlord or its agents, employees or contractors, and subject always to Section 23.7 and 28.2 and any subrogation provisions 
contained in the Work Letter, Tenant agrees to indemnify, save, defend (with counsel reasonably acceptable to Landlord,
unless required to be approved by Tenant’s insurer) and hold the Landlord Indemnitees harmless from and against any and all
Claims arising from injury or death to any person or damage to any property (x) occurring within or about the Premises or, 
(y) arising out of Tenant’s or Tenant’s employees’, agents’, contractors’ or invitees’ negligent or wrongful use or occupancy of
the Building or the Property (other than the Premises). Subject to Sections 23.7 and 28.2 and any subrogation provisions
contained in the Work Letter, Landlord agrees to indemnify, save, defend (at Tenant’s option and with counsel reasonably
acceptable to Tenant) and hold Tenant and its employees, agents and contractors harmless from and against any and all Claims
arising from injury or death to any person or damage to any property occurring within or about the Premises, the Building or the
Property arising out of the gross negligence or willful misconduct of Landlord or its agents, employees or contractors
misconduct.

     28.2. Notwithstanding anything in this Lease to the contrary, unless any such loss is due to the negligent or willful
misconduct of Landlord or its agents, employees or contractors with respect to any repair (or failure to make a repair) that
Landlord is responsible to make for an unreasonable period of time, Landlord shall not be liable to Tenant for and Tenant
assumes all risk of (a) damage or losses caused by fire, electrical malfunction, gas explosion, water damage of any type 
(including broken water lines, malfunctioning fire sprinkler systems, roof leaks or stoppages of lines), and (b) damage to 
personal property. Tenant further waives any claim for injury to Tenant’s business or loss of income relating to any such
damage or destruction of personal property as described in this Section. Notwithstanding anything in the foregoing or this
Lease to the contrary, except (x) as otherwise expressly provided herein, (y) as may be provided by Applicable Laws or (z) in the 
event of Tenant’s breach of Article 21 or Section 26.1 , in no event shall Landlord or Tenant be liable to the other for any
consequential, special or indirect damages arising out of this Lease.

      28.3. Landlord shall not be liable for any damages arising from any act, omission or neglect of any other tenant in the
Building or the Property, or of any other unaffiliated third party (provided that nothing in this Section 28.3 shall be deemed to 
relieve Landlord of its repair and maintenance obligations as set forth in this Lease).

     28.4. Tenant acknowledges that security devices and services, if any, while intended to deter crime, may not in given
instances prevent theft or other criminal acts. Landlord shall not be liable for injuries or losses caused by criminal acts of third
parties, and Tenant assumes the
  
                                                                  43


risk that any security device or service may malfunction or otherwise be circumvented by a criminal. If Tenant desires protection
against such criminal acts, then Tenant shall, at Tenant’s sole cost and expense, obtain appropriate insurance coverage.

     28.5. The provisions of this Article shall survive the expiration or earlier termination of this Lease.
29. Assignment or Subletting .
      29.1. Except as hereinafter expressly permitted, Tenant shall not, either voluntarily or by operation of Applicable Laws,
directly or indirectly sell, hypothecate, assign, pledge, encumber or otherwise transfer this Lease, or sublet the Premises (each, a
“ Transfer ”), without Landlord’s prior written consent. Notwithstanding the foregoing, Tenant shall have the right to Transfer
without Landlord’s prior written consent the Premises or any part thereof to (i) any person that as of the date of determination 
(and is contemplated to so remain), controls, is controlled by, or is under common control with Tenant (“ Tenant’s Affiliate ”),
or (ii) any successor to Tenant by merger, consolidation, acquisition of all or substantially all of Tenant’s assets or ownership
interests, or corporate reorganization, provided that (x) such merger, consolidation, acquisition of all or substantially all of 
Tenant’s assets or ownership interests, or corporate reorganization is for a good business purpose and not principally for the
purpose of transferring this Lease in violation of this provision, (y) the resulting tenant under this Lease has a net worth at least 
equal to or greater than $500,000,000 , and (z) any such successor to Tenant agrees in writing to assume all of the terms, 
covenants and conditions of this Lease arising after the effective date of such assignment (together with Transfers to Tenant’s
Affiliates, “ Exempt Transfers ”). In the event of an Exempt Transfer, Tenant shall notify Landlord in writing at least ten
(10) days prior to the effectiveness of such Exempt Transfer and otherwise comply with the requirements of this Lease regarding 
such Transfer. For purposes of Exempt Transfers, “control” requires both (a) owning (directly or indirectly) more than fifty 
percent (50%) of the stock or other equity interests of another person and (b) possessing, directly or indirectly, the power to 
direct or cause the direction of the management and policies of such person. In no event shall Tenant perform a Transfer (other
than an Exempt Transfer) to or with an entity that is a tenant at the Property or that is in then-active discussions or negotiations
(as evidenced by exchanges of proposals or communications) with Landlord or an affiliate of Landlord to lease premises at the
Property or a property owned by Landlord or an affiliate of Landlord in Kendall Square so long as Landlord or such affiliate has
comparable space available for lease in Kendall Square for a comparable term, as reasonably determined by Landlord.
Notwithstanding anything to the contrary contained in this Section 29.1 , so long as Tenant’s stock is publicly traded on a
nationally recognized exchange, neither a public offering of Tenant’s stock nor the transfer from time to time of Tenant’s stock
over a nationally recognized exchange shall not be deemed a Transfer and shall not require Landlord’s consent.

     29.2. In the event Tenant desires to effect a Transfer, then, at least fifteen (15) but not more than ninety (90) days prior to 
the date when Tenant desires the assignment or sublease to be effective (the “ Transfer Date ”), Tenant shall provide written
notice to Landlord (the “ Transfer Notice ”) containing information (including references) concerning the character of the
proposed transferee, assignee or sublessee; the
  
                                                                  44


Transfer Date; any ownership or commercial relationship between Tenant and the proposed transferee, assignee or sublessee;
and the consideration and all other material terms and conditions of the proposed Transfer, all in such detail as Landlord shall
reasonably require.

      29.3. Landlord, in determining whether consent should be given to a proposed Transfer, may give consideration to (a) the 
financial strength of such transferee, assignee or sublessee (notwithstanding Tenant remaining liable for Tenant’s
performance), and (b) any change in use that such transferee, assignee or sublessee proposes to make in the use of the 
Premises and (c) Landlord’s desire to exercise its rights under Section 29.8 (to the extent applicable) to cancel this Lease. In no
event shall Landlord be deemed to be unreasonable for declining to consent to a Transfer to a transferee, assignee or sublessee
of poor reputation, lacking financial qualifications or seeking a change in the Permitted Use, or jeopardizing directly or indirectly
the status of Landlord or any of Landlord’s affiliates as a Real Estate Investment Trust under the Internal Revenue Code of 1986
(as the same may be amended from time to time, the “ Revenue Code ”). Notwithstanding anything contained in this Lease to
the contrary, (w) no Transfer shall be consummated on any basis such that the rental or other amounts to be paid by the 
occupant, assignee, manager or other transferee thereunder would be based, in whole or in part, on the income or profits
derived by the business activities of such occupant, assignee, manager or other transferee; (x) Tenant shall not furnish or 
render any services to an occupant, assignee, manager or other transferee with respect to whom transfer consideration is
required to be paid, or manage or operate the Premises or any capital additions so transferred, with respect to which transfer
consideration is being paid; (y) Tenant shall not consummate a Transfer with any person in which Landlord owns an interest, 
directly or indirectly (by applying constructive ownership rules set forth in Section 856(d)(5) of the Revenue Code); and 
(z) Tenant shall not consummate a Transfer with any person or in any manner that could cause any portion of the amounts 
received by Landlord pursuant to this Lease or any sublease, license or other arrangement for the right to use, occupy or
possess any portion of the Premises to fail to qualify as “rents from real property” within the meaning of Section 856(d) of the 
Revenue Code, or any similar or successor provision thereto or which could cause any other income of Landlord to fail to
qualify as income described in Section 856(c)(2) of the Revenue Code. 

     29.4. The following are conditions precedent to a Transfer or to Landlord considering a request by Tenant to a Transfer:
            (a) Tenant shall remain fully liable under this Lease during the unexpired Term;

          (b) Tenant shall reimburse Landlord for Landlord’s reasonable and actual third party costs and expenses, including
reasonable attorneys’ fees, charges and disbursements incurred in connection with the review, processing and documentation
of such request;

           (c) If Tenant’s transfer of rights or sharing of the Premises (other than with respect to any Exempt Transfer) provides
for the receipt by, on behalf of or on account of Tenant of any consideration of any kind whatsoever (including a premium
rental for a sublease or lump sum payment for an assignment, but excluding Tenant’s reasonable costs in negotiating the
sublease or assignment and marketing and subleasing the Premises, and in preparing the applicable portion of the Premises for
occupancy by such subtenant or assignee) in excess of the
  
                                                                  45


rental and other charges due to Landlord under this Lease, Tenant shall pay fifty percent (50%) of all of such excess to 
Landlord, after making deductions for any reasonable legal and marketing expenses, tenant improvement funds expended by
Tenant, alterations, architectural/engineering costs, brokerage commissions, attorneys’ fees and free rent actually paid by
Tenant. If such consideration consists of cash paid to Tenant, payment to Landlord shall be made upon receipt by Tenant of
such cash payment;

          (d) The proposed transferee, assignee or sublessee shall agree that, in the event Landlord gives such proposed
transferee, assignee or sublessee notice that Tenant is in Default under this Lease, such proposed transferee, assignee or
sublessee shall thereafter make all payments otherwise due Tenant directly to Landlord, which payments shall be received by
Landlord without any liability being incurred by Landlord, except to credit such payment against those due by Tenant under
this Lease, and any such proposed transferee, assignee or sublessee shall agree to attorn to Landlord or its successors and
assigns should this Lease be terminated for any reason; provided , however, that in no event shall Landlord or its Lenders,
successors or assigns be obligated to accept such attornment;

            (e) Landlord’s consent to any such Transfer shall be effected on Landlord’s reasonable forms;

            (f) Tenant shall not then be in Default hereunder;

            (g) Such proposed transferee, assignee or sublessee’s use of the Premises shall be the same as the Permitted Use;

          (h) Landlord shall not be bound by any provision of any agreement pertaining to the Transfer, except for Landlord’s
written consent to the same;

            (i) Tenant shall pay all transfer and other taxes (including interest and penalties) assessed or payable for any
Transfer;

            (j) Landlord’s consent (or waiver of its rights) for any Transfer shall not waive Landlord’s right to consent to any later
Transfer;

          (k) Tenant shall deliver to Landlord one executed copy of any and all written instruments evidencing or relating to the
Transfer; and

          (l) If such Transferee shall be permitted to engage in any laboratory use, a list of Hazardous Materials (as defined in
Section 21.7 ), certified by the proposed transferee, assignee or sublessee to be true and correct, that the proposed transferee,
assignee or sublessee intends to use or store in the Premises. Additionally, Tenant shall deliver to Landlord, on or before the
date any proposed transferee, assignee or sublessee takes occupancy of the Premises, all of the items relating to Hazardous
Materials of such proposed transferee, assignee or sublessee as described in Section 21.2 .

     29.5. Any Transfer that is not in compliance with the provisions of this Article shall be void and shall, at the option of
Landlord, terminate this Lease. Tenant shall cause each Transferee (including any transferee under an Exempt Transfer), for the
benefit of Landlord, to
  
                                                                  46


reaffirm, on behalf of such Transferee, the representations of, and to otherwise comply with the obligations set forth in,
Section 37, and it shall be reasonable for Landlord to refuse to consent to a Transfer in the absence of such reaffirmation and 
compliance. Tenant agrees that breach of the representations and warranties set forth in Section 37, shall at Landlord’s election
compliance. Tenant agrees that breach of the representations and warranties set forth in Section 37, shall at Landlord’s election
be a default under this Lease for which there shall be no cure.

     29.6. The consent by Landlord to a Transfer shall not relieve Tenant or proposed transferee, assignee or sublessee from
obtaining Landlord’s consent to any further Transfer, nor shall it release Tenant or any proposed transferee, assignee or
sublessee of Tenant from full and primary liability under this Lease.

     29.7. Notwithstanding any Transfer, Tenant shall remain fully and primarily liable for the payment of all Rent and other
sums due or to become due hereunder, and for the full performance of all other terms, conditions and covenants to be kept and
performed by Tenant. The acceptance of Rent or any other sum due hereunder, or the acceptance of performance of any other
term, covenant or condition thereof, from any person or entity other than Tenant shall not be deemed a waiver of any of the
provisions of this Lease or a consent to any Transfer.

      29.8. If Tenant delivers to Landlord a Transfer Notice indicating a desire to transfer this Lease to a proposed transferee,
assignee or sublessee (other than with respect to any Exempt Transfer or sublets not exceeding the lesser of one full floor and
40% of the Premises in the aggregate) for at least 85% of the then remaining term (in the case of a sublease), then Landlord shall
have the option, exercisable by giving notice to Tenant at any time within ten (10) days after Landlord’s receipt of such Transfer
Notice, to terminate (in each case (a) as of the date specified in the Transfer Notice as the Transfer Date, and (b) except for 
those provisions that, by their express terms, survive the expiration or earlier termination hereof) this Lease (y) in its entirety, if 
such Transfer Notice relates to an assignment of this Lease or a sublease of 80% or more of the Premises, or (z) solely with 
respect to the portion of the Premises subject to such Transfer Notice, if such Transfer Notice relates to a sublease of less than
80% of the Premises but at least one full floor of the Building. If Landlord exercises such option, then Tenant shall have the
right to withdraw such Transfer Notice by delivering to Landlord written notice of such election within five (5) business days 
after Landlord’s delivery of notice electing to exercise Landlord’s option to terminate this Lease. In the event Tenant withdraws
the Transfer Notice as provided in this Section, this Lease shall continue in full force and effect in its entirety. No failure of
Landlord to exercise its option to terminate this Lease shall be deemed to be Landlord’s consent to a proposed Transfer. If this
Lease shall be terminated or released as to a portion of the Premises only pursuant to clause (z), above, Base Rent, the Property
Management Fee, Tenant’s Pro Rata Share and the number of parking spaces for Tenant’s use, shall be readjusted
proportionately according to the ratio that the Rentable Area in the portion of the Premises surrendered compares to the
Rentable Area of Tenant’s remaining Premises, and Landlord and Tenant shall enter into a suitable and mutually acceptable
amendment to this Lease reflecting the same.

     29.9. If Tenant sublets the Premises or any portion thereof, Tenant hereby irrevocably authorizes Landlord, during the
continuance of a Default, to collect rent from any such subletting (and upon notice any subtenant shall pay directly to
Landlord) and apply the net amount collected toward Tenant’s obligations under this Lease.
  
                                                                  47


30. Subordination and Attornment .
      30.1. Tenant agrees that this Lease and the rights of Tenant hereunder will be subject and subordinate to any lien of the
holder of any present or future mortgage, and to the rights of any lessor under any ground or improvements lease of the
Building (all mortgages and ground or improvements leases of any priority are collectively referred to in this Lease as
“Mortgage,” and the holder or lessor thereof from time to time as a “ Mortgagee ”), and to all advances and interest thereunder
and all modifications, renewals, extensions and consolidations thereof; provided that any subordination of this Lease shall be
conditioned upon Landlord delivering to Tenant a written, recordable subordination, non-disturbance and attornment
agreement (“ SNDA ”) from the Mortgagee seeking to have this Lease subordinated to its interest substantially in the form
attached as Exhibit J (or in such other commercially reasonable form as may be reasonably acceptable to the parties to such
agreement). Landlord represents and warrants that the only mortgage to which this Lease is subject as of the execution date is
that certain mortgage to Wells Fargo Bank, NA (the “ Existing Mortgagee ”). Landlord shall provide to Tenant, within 30 days
after the date of this Lease, an executed SNDA from the Existing Mortgagee.

      30.2. Notwithstanding the foregoing, Tenant shall execute and deliver upon demand such further reasonable instrument or
instruments as may be reasonably acceptable to the parties to such agreement evidencing such subordination of this Lease to
the lien of any such mortgage or mortgages or lease in which Landlord is tenant as may be reasonably required by Landlord. If
any such Mortgagee so elects, however, this Lease shall be deemed prior in lien to any such lease or mortgage upon or
including the Premises regardless of date and Tenant shall execute a statement in writing to such effect at Landlord’s request.
Tenant’s failure to execute any document required from Tenant under this Section within ten (10) business days after written 
request therefor, if such failure continues for more than five (5) days after Landlord gives Tenant written notice thereof (which 
notice shall state, in bold and prominent print, that failure to reply shall result in a Default under this Section 20.2), shall be a 
Default for which this Lease may be terminated without further notice.
      30.3. In the event any proceedings are brought for foreclosure, or in the event of the exercise of the power of sale under
any mortgage or deed of trust made by Landlord covering the Premises, Tenant shall at the election of the purchaser at such
foreclosure or sale attorn to the purchaser upon any such foreclosure or sale and recognize such purchaser as Landlord under
this Lease, so long as such purchaser recognizes Tenant as the tenant under this Lease and all of its rights hereunder, including
this Article.

     30.4. If from time to time Landlord assigns this Lease or the rents payable hereunder to any Mortgagee, whether such
assignment is conditional in nature or otherwise, such assignment shall not be deemed an assumption by the assignee of any
obligations of Landlord; the assignee shall be responsible only for non-performance of Landlord’s obligations that occur after it
succeeds to, and only during the period it holds possession of, Landlord’s interest in the Premises after foreclosure or
voluntary deed in lieu of foreclosure.
  
                                                                48


31. Defaults and Remedies .
      31.1. Late payment by Tenant to Landlord of Rent and other sums due shall cause Landlord to incur costs not
contemplated by this Lease, the exact amount of which shall be extremely difficult and impracticable to ascertain. Such costs
include processing and accounting charges and late charges that may be imposed on Landlord by the terms of any mortgage or
trust deed covering the Premises. Therefore, if any installment of Rent due from Tenant is not received by Landlord within five
(5) business days after the date such payment is due, Tenant shall pay to Landlord (a) an additional sum of six percent (6%) of 
the overdue Rent as a late charge (provided that, with respect to the first late payment in any twelve (12) month period, no such 
late charge shall be due), plus (b) interest at an annual rate (the “ Default Rate ”) equal to the lesser of (a) twelve percent 
(12%) and (b) the highest rate permitted by Applicable Laws. The parties agree that this late charge represents a fair and 
reasonable estimate of the costs that Landlord shall incur by reason of late payment by Tenant and shall be payable as
Additional Rent to Landlord due with the next installment of Rent or within five (5) business days after Landlord’s demand,
whichever is earlier. Landlord’s acceptance of any Additional Rent (including a late charge or any other amount hereunder)
shall not be deemed an extension of the date that Rent is due or prevent Landlord from pursuing any other rights or remedies
under this Lease, at law or in equity.

     31.2. No payment by Tenant or receipt by Landlord of a lesser amount than the Rent payment herein stipulated shall be
deemed to be other than on account of the Rent, nor shall any endorsement or statement on any check or any letter
accompanying any check or payment as Rent be deemed an accord and satisfaction, and Landlord may accept such check or
payment without prejudice to Landlord’s right to recover the balance of such Rent or pursue any other remedy provided in this
Lease or in equity or at law. If a dispute shall arise as to any amount or sum of money to be paid by Tenant to Landlord
hereunder, Tenant shall have the right to make payment “under protest,” such payment shall not be regarded as a voluntary
payment, and there shall survive the right on the part of Tenant to institute suit for recovery of the payment paid under protest.

      31.3. If Tenant fails to pay any sum of money required to be paid by it hereunder, or shall fail to perform any other act on
its part to be performed hereunder, in each case within the applicable notice and cure period (if any) described in Section 31.4 ,
then Landlord may, without waiving or releasing Tenant from any obligations of Tenant, but shall not be obligated to, make
such payment or perform such act; provided that such failure by Tenant unreasonably interfered with the use of the Building or
the Property by any other tenant or with the efficient operation of the Building or the Property, or resulted or could have
resulted in a violation of Applicable Laws or the cancellation of an insurance policy maintained by Landlord. Notwithstanding
the foregoing, in the event of an emergency, Landlord shall have the right to enter the Premises upon such notice as is
reasonable under the circumstances, and act in accordance with its rights as provided elsewhere in this Lease. In addition to the
late charge described in Section 31.1 , Tenant shall pay to Landlord as Additional Rent all sums so paid or incurred by Landlord,
together with interest at the Default Rate, computed from the date such sums were paid or incurred.

     31.4. The occurrence of any one or more of the following events shall constitute a “ Default ” hereunder by Tenant:

          (a) Tenant abandons the Premises;
          (a) Tenant abandons the Premises;
  
                                                                  49


           (b) Tenant fails to make any payment of Rent, as and when due, or to satisfy its obligations under Article 19 , where
such failure shall continue for a period of five (5) Business Days after written notice thereof from Landlord to Tenant; 

          (c) Tenant fails to observe or perform any obligation or covenant contained herein (other than described in
Subsections 31.4(a) and 31.4(b) ) to be performed by Tenant, where such failure continues for a period of thirty (30) days after 
written notice thereof from Landlord to Tenant; provided that, if the nature of Tenant’s default is such that it reasonably
requires more than thirty (30) days to cure, Tenant shall not be deemed to be in Default if Tenant commences such cure within 
such period and thereafter diligently prosecute the same to completion;

          (d) Tenant makes an assignment for the benefit of creditors;

          (e) A receiver, trustee or custodian is appointed to or does take title, possession or control of all or substantially all of
Tenant’s assets and is not removed within 60 days;

          (f) Tenant files a voluntary petition under the United States Bankruptcy Code or any successor statute (as the same
may be amended from time to time, the “ Bankruptcy Code ”) or an order for relief is entered against Tenant pursuant to a
voluntary or involuntary proceeding commenced under any chapter of the Bankruptcy Code;

           (g) Any involuntary petition is filed against Tenant under any chapter of the Bankruptcy Code and is not dismissed
within sixty (60) days; 

          (h) Tenant fails to deliver an estoppel certificate in accordance with Article 20 ; or

          (i) Tenant’s interest in this Lease is attached, executed upon or otherwise judicially seized and such action is not
released within sixty (60) days of the action. 
released within sixty (60) days of the action. 

                 Notices given under this Section shall specify the alleged default and shall demand that Tenant perform the
provisions of this Lease or pay the Rent that is in arrears, as the case may be, within the applicable period of time, or quit the
Premises. No such notice shall be deemed a forfeiture or a termination of this Lease unless Landlord elects otherwise in such
notice.

     31.5. In the event of a Default by Tenant, and at any time thereafter, with or without notice or demand and without limiting
Landlord in the exercise of any right or remedy that Landlord may have, Landlord has the right to do any or all of the following:

           (a) Halt any Alterations and order Tenant’s contractors, subcontractors, consultants, designers and material
suppliers to stop work;

         (b) Terminate Tenant’s right to possession of the Premises by written notice to Tenant or by any lawful means, in
which case Tenant shall immediately surrender possession of the Premises to Landlord. In such event, Landlord shall have the
immediate right to peaceably                    BMR-650 E KENDALL B LLC,
                                             a Delaware limited liability company

                                                               and

                                              AVEO PHARMACEUTICALS, INC.,
                                                  a Delaware corporation


                                                    TABLE OF CONTENTS
  
                                                                                                                              Page  

1.        Lease of Premises                                                                                                       1  
2.        Basic Lease Provisions                                                                                                  2  
3.        Term                                                                                                                    5  
4.        Possession and Commencement Date                                                                                        5  
5.        Condition of Premises                                                                                                   7  
6.        Rentable Area                                                                                                           7  
7.        Rent                                                                                                                    7  
8.        Rent Adjustments                                                                                                        8  
9.        Operating Expenses                                                                                                      8  
10.    Taxes on Tenant’s Property                                                                                                 13  
11.    Security Deposit                                                                                                           14  
12.    Use                                                                                                                        15  
13.    Rules and Regulations, CC&Rs, Parking Facilities and Common Areas                                                          18  
14.    Property Control by Landlord                                                                                               21  
15.    Quiet Enjoyment                                                                                                            22  
16.    Utilities and Services                                                                                                     22  
17.    Alterations                                                                                                                25  
18.    Repairs and Maintenance                                                                                                    28  
19.       Liens                                                                                                                   30  
19.    Liens                                                             30  
20.    Estoppel Certificate                                              31  
21.    Hazardous Materials                                               32  
22.    Odors and Exhaust                                                 35  
23.    Insurance; Waiver of Subrogation                                  36  
24.    Damage or Destruction                                             38  
25.    Eminent Domain                                                    41  
26.    Surrender                                                         42  
27.    Holding Over                                                      42  
28.    Indemnification and Exculpation                                   43  
29.    Assignment or Subletting                                          44  
30.    Subordination and Attornment                                      48  
31.    Defaults and Remedies                                             49  
  
                                                   i


                                          TABLE OF CONTENTS
                                              (continued)
  
                                                                     Page  

32.    Bankruptcy                                                        53  
33.    Brokers                                                           54  
34.    Definition of Landlord                                            54  
35.    Limitation of Liability                                           55  
36.    Joint and Several Obligations                                     56  
37.    Representations                                                   56  
38.    Confidentiality                                                   57  
39.    Notices                                                           57  
40.    Rooftop Installation Area                                         57  
41.    Miscellaneous                                                     59  
42.    Options to Extend Term                                            61  
43.    Right of First Offer                                              62  
44.    Right of First Refusal                                            64  
  
                                                   ii


                                          TABLE OF DEFINITIONS
                                TABLE OF DEFINITIONS
  
                                                                   Page  

Accountant                                                            12  
ADA                                                                   17  
Additional Rent                                                        7  
Affected Areas                                                        38  
Alterations                                                           25  
ANSI                                                                  42  
Applicable Laws                                           3, 5, 8, 9, 10  
Available ROFO Premises                                               63  
Available ROFR Premises                                               64  
Bankruptcy Code                                                       50  
Base Rent                                                              3  
Baseball Arbitrator                                                   61  
BMBL                                                                  33  
Broker                                                                54  
Building                                                               1  
CC&R                                                                  18  
Claims                                                                17  
Common Area                                                            1  
Cosmetic Alterations                                                  26  
Damage Repair Estimate                                                39  
Default                                                              49  
Default Rate                                                         49  
DHHS                                                                 33  
Discount Rate                                                        51  
Execution Date                                                        1  
Exempt Transfers                                                     44  
Existing Mortgagee                                                   48  
Exit Survey                                                          42  
FMV                                                                  61  
Garage                                                               20  
Garage Operator                                                      20  
Garage Parking Spaces                                                20  
Generator                                                            24  
Governmental Authority                                                8  
Hazardous Material                                                   32  
Hazardous Materials Documents                                        33  
HVAC                                                                  5  
Independent Review                                                   11  
L/C Security                                                         14  
Land                                                                  1  
Landlord                                                          1, 54  
Landlord Delay                                                        6  
Landlord Indemnitees                                                 17  
Landlord Parties                                                     37  
  
                                         iii


                                TABLE OF DEFINITIONS
                                     (continued)
  
                                                                      Page  

Lease                                                                      1  
Lender                                                                    17  
Mortgagee                                                                 48  
MWRA                                                                      18  
New Tenant                                                                35  
Notice of Marketing                                                       63  
Notice of Offer                                                           64  
OFAC                                                                      56  
Operating Expenses                                                         8  
Option                                                                    61  
Option Notice                                                             61  
Phase 1 Premises                                                           5  
Phase 1 Premises Deadline                                                  5  
Phase 1 Premises Rent Commencement Date                                    5  
Phase 1 Premises Tenant Improvements                                       5  
Phase 2 Premises                                                           5  
Phase 2 Premises Rent Commencement Date                                    5  
Phase 2 Premises Tenant Improvements                                       5  
Premises                                                                   1  
Property                                                                   1  
Property Management Fee                                                   11  
Property Operations Agreements                                            18  
REBA                                                                      61  
REFA                                                                      61  
Revenue Code                                                              45  
ROFO                                                                      63  
ROFR                                                                      64  
Rooftop Installation Area                                                 57  
Rules and Regulations                                                     18  
Security Deposit                                                          14  
Signage                                                                   16  
SNDA                                                                      48  
Specialty Alterations                                                     27  
Substantial Completion                                                     6  
Substantially Complete                                                     6  
Tenant                                                                     1  
Tenant Improvements                                                        6  
Tenant Premises Notice                                                     2  
Tenant’s Affiliate                                                        44  
Tenant’s Parking Spaces                                                   19  
Tenant’s Rooftop Equipment                                                58  
Tenant’s Share                                                            10  
Term                                                                       5  
Term Expiration Date                                                       5  
Termination Notice                                                        39  
  
                                                   iv


                                          TABLE OF DEFINITIONS
                                               (continued)
  
                                                                      Page  
TI Allowance                    6  
TI Deadline                     6  
Transfer                       44  
Transfer Date                  44  
Transfer Notice                44  
UBC                            34  
Work Letter                     6  
  
                  v
                                                                LEASE

     THIS LEASE (this “ Lease ”) is entered into as of this 9th day of May, 2012 (the “ Execution Date ”), by and between BMR-
650 E Kendall B LLC, a Delaware limited liability company (“ Landlord ”), and AVEO Pharmaceuticals, Inc., a Delaware
corporation (“ Tenant ”).

                                                              RECITALS

     A. WHEREAS, Landlord owns certain real property commonly known as Parcel B and described further on Exhibit A-1
attached hereto (the “ Land ”) and the improvements on the Property located at 650 East Kendall Street, Cambridge,
Massachusetts, including the building and the Garage (as defined in Section 13.5) (collectively, the “Building”) in which the
Premises (as defined below) are located; and

     B. WHEREAS, Landlord wishes to lease to Tenant, and Tenant desires to lease from Landlord, certain premises (the “ 
Premises ”) located on a portion of the fourth (4th) floor, and the entire fifth (5th) and sixth (6th) floors, together with certain off-
floor mechanical areas, of the Building, pursuant to the terms and conditions of this Lease, as detailed below.

                                                            AGREEMENT

     NOW, THEREFORE, Landlord and Tenant, in consideration of the mutual promises contained herein and for other good
and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, and intending to be legally bound,
agree as follows:

1. Lease of Premises .
      1.1. Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord, the Premises, as shown on Exhibit A
attached hereto for use by Tenant in accordance with the Permitted Use (as defined below) and no other uses. The Building,
Land and all landscaping, parking facilities, private drives and other improvements and appurtenances located thereon and
related thereto, including the Building and other buildings located on the Land, are hereinafter collectively referred to as the “ 
Property .” All portions of the Building and Property that are for the non-exclusive use of the tenants of the Property, such as
service corridors, elevators, loading docks, public restrooms, public entranceways, lobbies and stairways, electric and
telephone closets (other than those exclusively serving the Premises, if any), janitor closets, and other areas from time to time
designated as common areas by Landlord (all to the extent located in the Building or on the Property) are hereinafter referred to
as “ Common Area .” The Premises exclude Common Areas, fan rooms, mechanical rooms, elevators wells, pipes, ducts,
conduits, wires and appurtenant fixtures serving other parts of the Property (exclusively or in common), and any exterior walls
(including without limitation the roof and roof system) and structural members of the Building. If the Premises include less than
the entire rentable area of any floor, then the Premises also exclude the common corridors, elevator lobby and toilets located on
such floor.


      Tenant shall have the right, on or before to June 1, 2012, in each case by written notice (a “ Tenant Premises Notice ”) to
Landlord identifying the alternative demising of the Premises proposed by Tenant, to (x) reduce or expand the portion of the 
Premises located on the fourth floor by adjusting the location of the demising walls between the Premises and contiguous
leaseable areas on the fourth floor by an amount not to exceed five thousand (5,000) square feet of Rentable Area, provided that 
the remainder of the leaseable areas on the fourth floor are readily leaseable for multi-tenant purposes in a first class office and
laboratory building, as reasonably determined by Landlord; there is no adverse impact on Building systems or structure as a
result of such adjustment; and/or (y) substitute alternative, existing off-floor mechanical locations in the Building for the off-
floor mechanical portions of the Premises, provided that such areas are, in Landlord’s reasonable determination, of an
floor mechanical portions of the Premises, provided that such areas are, in Landlord’s reasonable determination, of an
equivalent aggregate Rentable Area, do not impose an inequitable allocation or use of similar mechanical spaces for tenant
spaces in the Building, do not reduce any leaseable areas of the Building, and do not adversely affect Building operations or
access. Within 10 days following the giving of a Tenant Premises Notice, Landlord shall approve the proposed revised Premises
or disapprove such proposal with specific reasons therefor. Landlord’s failure to respond within such ten day period shall be
deemed approval by Landlord. Following the adjustment of the Premises in accordance with this Section, the parties shall enter
into an amendment to this Lease substituting the revised Premises plans for the applicable floors of the Premises for the
Premises plans initially attached as Exhibit A hereto, and the annual Base Rent, Tenant’s Parking Spaces, and Tenant’s Pro Rata
Share (as each term is defined below) shall be adjusted accordingly based on the change in Rentable Area of the Premises as
determined by Landlord in accordance with Article 6, below.

2. Basic Lease Provisions . For convenience of the parties, certain basic provisions of this Lease are set forth herein. The
provisions set forth herein are subject to the remaining terms and conditions of this Lease and are to be interpreted in light of
such remaining terms and conditions.

     2.1. This Lease shall take effect upon the Execution Date and, except as specifically otherwise provided within this Lease,
each of the provisions hereof shall be binding upon and inure to the benefit of Landlord and Tenant from the date of execution
and delivery hereof by all parties hereto.

    2.2. In the definitions below, each current Rentable Area (as defined below) is expressed in rentable square footage.
Rentable Areas and “ Tenant’s Pro Rata Shares ” are all subject to adjustment only as expressly provided in this Lease.
  
                                                                             Means the Following (As of the
                                                                                Means the Following (As of the
                    Definition or Provision                                           Execution Date)
                    Rentable Area of Premises                                      126,065 square feet
                    Rentable Area of Building                                      291,498 square feet
                    Rentable Area of Lab Building                                  278,736 square feet
                    Tenant’s Pro Rata Share of Building                                 43.25%
                    Tenant’s Pro Rata Share of Lab Building                             45.23%
  
                                                                2


   2.3. Initial monthly and annual installments of Base Rent for the Premises (“ Base Rent ”) as of the Phase 1 Premises Rent
Commencement Date (as defined in Section 4.1 below), subject to adjustment under this Lease:
  
                                                                                      Base Rent per 
                                                              Square Feet of          Square Foot of 
                                                              Rentable Area          Rentable Area of      Monthly Base   Annual Base
                                                                Rentable Area           Rentable Area of     Monthly Base          Annual Base
Dates                                                          for the Premises          the Premises           Rent                  Rent       
Phase 1 Premises Rent Commencement Date – the date                     126,065          $54.50 annually        $572,545.21        $6,870,542.50  
  immediately preceding the first (1 st ) anniversary of
  the Phase 1 Premises Rent Commencement Date                                                                                  

     As further described in Section 4.1, below, Base Rent shall be prorated for the Premises between the Phase 1 and Phase 2 
Premises, and only payable with respect to the Phase 1 Premises, until such time as the Phase 2 Premises Rent Commencement
Date occurs.
     2.4. Term Commencement Date: The date upon which Landlord delivers the Premises to Tenant in its “as is” condition as
of the date hereof with a temporary demising wall constructed on the 4th floor of the Building that is reasonably sufficient for
Tenant to secure such portion of the Premises, which date Landlord shall cause to occur no later than May 31, 2012. 

     2.5. Estimated Term Expiration Date: December 31, 2024. 

     2.6. Security Deposit: $2,862,726.

     2.7. Permitted Use: Office and laboratory use in conformity with all federal, state, municipal and local laws, codes,
ordinances, rules and regulations of Governmental Authorities (as defined below), committees, associations, or other regulatory
committees, agencies or governing bodies having jurisdiction over the Premises, the Building, the Property, Landlord or Tenant,
including both statutory and common law and hazardous waste rules and regulations (“ Applicable Laws ”). Tenant shall obtain
validation by any medical review board or other similar governmental licensing of the Premises required for the Permitted Use.
  
                                                                     3


                  2.8. Address for Rent Payment:                  BMR-650 E Kendall B LLC

                                                                  Pursuant   to the following wire instructions:
                                                                  Name of beneficiary: BMR-650 E Kendall B LLC
                                                                  Account number: 153495105154
                                                                  Bank Name: US Bank
                                                                  Routing/Transit #: 122235821
                                                                  Branch Name & Address: San Diego Main
                                                                  600 W Broadway #100
                                                                  San Diego, CA 92101

                  2.9. Address for Notices to Landlord:           BMR-650 E Kendall B LLC

                                                                  17190 Bernardo Center Drive
                                                                  San Diego, California 92128
                                                                  Attn: Vice President, Real Estate   Counsel
                  2.10. Address for Notices to Tenant:            

                  Prior to the Rent Commencement Date:            AVEO Pharmaceuticals, Inc.
                                                                  75 Sidney Street
                                                                  Cambridge, MA 02139
                                                                  Attn: Chief Financial Officer

                  On or after the Rent Commencement Date:      At the Premises
                  With a copy to:                                 Langer & McLaughlin,     LLP
                                                                  855 Boylston Street
                                                                  Boston, MA 02116


                  2.11. The following Exhibits are attached hereto and incorporated herein by reference:
  
                         Exhibit A        Premises
                         Exhibit A-1      Land
                         Exhibit B        Work Letter
                         Exhibit B-1       Scope of Landlord’s Demising Work
                         Exhibit C        Acknowledgement of Rent Commencement        Date and Term Expiration Date
                         Exhibit D        Development Approvals
                         Exhibit E        Form of Letter of Credit
                         Exhibit F        Rules and Regulations
       Exhibit F          Rules and Regulations
       Exhibit G          Tenant’s Personal Property
       Exhibit H          Form of Estoppel Certificate
       Exhibit I          SNDA
       Exhibit J          Rooftop Installation Area
       Exhibit K          Kendall Square
       Exhibit L          Tenant’s Signage Location
  
                                                   4
3. Term . The actual term of this Lease (as the same may be extended pursuant to Article 42 hereof, and as the same may be
earlier terminated in accordance with this Lease, the “ Term ”) shall commence on the Term Commencement Date and end on the
date that is twelve (12) years after the actual Phase 1 Premises Rent Commencement Date (such date, the “ Term Expiration Date
”), subject to earlier termination of this Lease as provided herein, provided that if the Phase 1 Premises Rent Commencement
Date is not the first day of a calendar month, then the Term Expiration Date shall be the last day of the calendar month in which
the twelfth (12 th ) anniversary of the Phase 1 Premises Rent Commencement Date occurs. 

4. Possession and Commencement Date .
      4.1. Landlord has delivered to Tenant, broom clean and free of occupants, and Tenant has accepted possession of, the
Premises as of the date hereof. Landlord represents and warrants to Tenant that, as of the date hereof, the heating, ventilation
and air-conditioning (“HVAC”), electrical, life safety and plumbing systems of the Building are in good working condition and,
to the best of Landlord’s knowledge, not in violation of Applicable Laws applicable to office and laboratory use, generally.
Tenant shall undertake its Tenant Improvements and occupy the Premises for the conduct of its business in two phases. The “ 
Phase 1 Premises ” shall consist of not less than twenty thousand (20,000) square feet of Rentable Area on the sixth (6th) floor 
of the Building identified by Tenant to Landlord no later than June 1, 2012 (the “ Phase 1 Premises Deadline ”). If Tenant fails to
provide Landlord with such notice by the Phase 1 Premises Deadline, then the Phase 1 Premises shall be as shown on Exhibit B-
2 attached hereto. Promptly following the Phase 1 Premises Deadline, the parties shall enter into a written instrument confirming
the square footage of Rentable Area of the Phase 1 Premises. The “ Phase 2 Premises ” shall consist of the balance of the
Premises. The Rent Commencement Date shall be determined separately for each Phase and Base Rent shall be prorated based
on the ratio of square footage of the Phase 1 Premises to the entire Premises until such time as the “Rent Commencement Date” 
occurs with respect to the entire Premises (i.e., until such time as the Phase 2 Premises Rent Commencement Date occurs). The “ 
Phase 1 Premises Rent Commencement Date ” shall be the earlier of (a) the Date earlier to occur of (i) Substantial Completion of 
the work described on Exhibit B with respect to the Phase 1 Premises (the “ Phase 1 Premises Tenant Improvements ”), and
(ii) January 1, 2013 and (b) the date on which Tenant has occupied any portion of the Phase 1 Premises for the conduct of its 
business, as opposed to occupying any portion of the Phase 1 Premises for the installation of the Tenant Improvements (as
defined below). The “ Phase 2 Premises Rent Commencement Date ” shall be the earlier of (y) the Date that is the earlier to occur 
of (i) Substantial Completion of the work described on Exhibit B with respect to the Phase 2 Premises (the “ Phase 2 Premises
Tenant Improvements ” and, together with the Phase 1 Premises Tenant Improvements, the
  
                                                                5


“ Tenant Improvements ”), and (ii) November 1, 2013 and (z) the date on which Tenant has occupied any portion of the Phase 2 
Premises for the conduct of its business, as opposed to occupying any portion of the Phase 2 Premises for the installation of
the Tenant Improvements. Each of the Phase 1 Premises Rent Commencement Date and the Phase 2 Premises Rent
Commencement Date shall be subject to extension for Landlord Delay as further described in Section 4 of Exhibit B hereto. Each
party shall execute and deliver to the other written acknowledgment of the actual Commencement Date, the actual Phase 1
Premises Rent Commencement Date, the actual Phase 2 Premises Rent Commencement Date and/or the Term Expiration Date
within ten (10) business days after request by the other party, substantially in the form attached as Exhibit C hereto. Failure to
execute and deliver such acknowledgment, however, shall not affect the Phase 1 Premises Rent Commencement Date, the Phase
2 Premises Rent Commencement Date, the Term Expiration Date or Landlord’s or Tenant’s liability hereunder. The term “ 
Substantially Complete ” or “ Substantial Completion ” means that the applicable Phase of Tenant Improvements is
substantially complete in accordance with the Approved Plans (as defined in Exhibit B hereto), except for minor punch list items,
and that Tenant is able to lawfully occupy the Premises for the conduct of its business in accordance with the Permitted Use.

      4.2. Tenant shall cause the Tenant Improvements to be constructed in the Premises pursuant to the Work Letter attached
hereto as Exhibit B (the “ Work Letter ”) at a cost to Landlord not to exceed Eighteen Million Nine Hundred Nine Thousand
Seven Hundred Fifty and 00/100 Dollars ($18,909,750.00) (based upon One Hundred Fifty and 00/100 Dollars ($150.00) per
square foot of Rentable Area (as defined below)) (the “ TI Allowance ”). The TI Allowance may be applied to the costs of
(s) construction, (t) building permits and other permits, approvals, taxes, fees, charges and levies by Governmental Authorities 
(as defined below) for permits or for inspections of the Tenant Improvements, and (u) costs and expenses for labor, material, 
equipment and fixtures. In no event shall the TI Allowance be used for (v) the cost of work that is not authorized by the 
Approved Plans (as defined in the Work Letter) or otherwise approved in writing by Landlord, (w) payments to Tenant or any 
affiliates of Tenant, (x) Tenant’s soft costs or the purchase of any furniture, personal property or other non-building system
equipment, (y) costs resulting from any default by Tenant of its obligations under this Lease or (z) costs to extent recoverable 
by Tenant from a third party (e.g., insurers, warrantors, or tortfeasors). Notwithstanding the foregoing to the contrary, Tenant
may apply up to ten percent (10%) of the TI Allowance toward the costs of Tenant’s architectural, engineering, and project
management fees, data/telecom cabling, relocation expenses, and an additional amount up to ten percent (10%) of the TI 
Allowance towards the costs of Tenant’s furniture, fixtures and equipment installation related to the initial occupancy of the
Premises. In no event shall any unused TI Allowance entitle Tenant to a credit against Rent payable under this Lease. Tenant
shall have until May 31, 2014 (the “ TI Deadline ”) to requisition the unused portion of the TI Allowance, after which date
shall have until May 31, 2014 (the “ TI Deadline ”) to requisition the unused portion of the TI Allowance, after which date
Landlord’s obligation to fund such costs shall expire.

     4.3. The Phase 1 Premises and Phase 2 Premises are sometimes generically referred to herein as a “Phase”.
  
                                                                6


    4.4. Prior to entering upon the Premises, Tenant shall furnish to Landlord evidence satisfactory to Landlord that insurance
coverages required of Tenant under the provisions of Article 23 are in effect.
coverages required of Tenant under the provisions of Article 23 are in effect.

5. Condition of Premises . Tenant acknowledges that neither Landlord nor any agent of Landlord has made any
representation or warranty with respect to the condition of the Premises, the Building or the Property, or with respect to
the suitability of the Premises, the Building or the Property for the conduct of Tenant’s business, except as expressly set
forth in this Lease. Without in any way derogating from Landlord’s ongoing maintenance, repair and restoration
obligations set forth elsewhere in this Lease, Tenant acknowledges that (a) it is familiar with the condition of the Premises 
and agrees to take the same in its condition “as is” as of the Execution Date and (b) Landlord shall have no obligation to 
alter, repair or otherwise prepare the Premises for Tenant’s occupancy or to pay for or construct any improvements to the
Premises, except with respect to the TI Allowance; provided, however, that Landlord shall separately demise that portion
of the Premises located on the fourth (4th) floor of the Building separately as shown on Exhibit B-1 attached hereto and
furnish and provide a reception desk in the main building lobby as further provided in Exhibit B , at Landlord’s sole cost
and expense (in addition to the TI Allowance).

6. Rentable Area . The Rentable Areas initially set forth herein are deemed conclusive between the parties and are not subject to
remeasurement, except that in the event that the size of the Premises or Building is actually reduced or expanded pursuant to the
provisions of Articles 1, 24, 25, 43 or 44 below, the Rentable Areas (and, as applicable, Tenant’s Pro Rata Share) shall be
adjusted as reasonably calculated by Landlord’s architect in a manner consistent with Landlord’s initial determination of
Rentable Areas for the Premises and the Building.

7. Rent .
     7.1. Tenant shall pay to Landlord as Base Rent for the Premises, commencing on the Phase 1 Premises Rent
Commencement Date, the sums set forth in Section 2.3 , subject to the rental adjustments provided in Section 4.1 and Article 8
hereof. Base Rent shall be paid in equal monthly installments, subject to the rental adjustments provided in Section 4.1 and
Article 8 hereof, each in advance on the first day of each and every calendar month during the Term.

      7.2. In addition to Base Rent, Tenant shall pay to Landlord as additional rent (“ Additional Rent ”) at times hereinafter
specified in this Lease (a) Tenant’s Share (as defined below) of Operating Expenses (as defined below), (b) the Property 
Management Fee (as defined below) and (c) any other amounts that Tenant assumes or agrees to pay under the provisions of 
this Lease that are owed to Landlord, including any and all other sums that may become due by reason of any default of Tenant
or failure on Tenant’s part to comply with the agreements, terms, covenants and conditions of this Lease to be performed by
Tenant, after notice and the lapse of any applicable cure periods.

     7.3. Base Rent and Additional Rent shall together be denominated “Rent.” Rent shall be paid to Landlord in lawful money
of the United States of America at the office of Landlord as set forth in Section 2.8 or to such other person or at such other 
place as Landlord may from time designate in writing. In the event the Phase 1 Rent Commencement Date or Phase 2 Rent
  
                                                                 7


Commencement Date occurs or the Term ends on a day other than the first day of a calendar month, then the Rent for such
fraction of a month shall be prorated for such period on the basis of a thirty (30) day month and shall be paid at the then-current
rate for such fractional month. All payments of Rent shall be made without set-off, deduction or offset except as expressly
provided in this Lease. Without limiting the foregoing, Tenant’s obligation to pay Rent shall be absolute, unconditional, and
independent and shall not be discharged or otherwise affected by any Applicable Laws now or hereafter applicable to the
Premises, or any other restriction on Tenant’s use, or, except as provided in Articles 24 and 25 , any casualty or taking, or any
failure by Landlord to perform or other occurrence; and Tenant assumes the risk of the foregoing and waives all rights now or
hereafter existing to quit or surrender the Premises or any part thereof, to terminate or cancel this Lease, or to assert any defense
in the nature of constructive eviction in any action seeking to recover rent (other than mandatory counterclaims). Subject to the
provisions of this Lease, however, Tenant shall have the right to injunctive relieve or to seek judgments for direct money
damages occasioned by Landlord’s breach of its Lease covenants (but may not set-off any such judgment against any rent or
other amount owing hereunder). Nothing in this Section 7.3 shall limit the exercise of Tenant’s express remedies on the terms
and conditions set forth in Sections 16.2 and  18.3 below).

8. Rent Adjustments . Base Rent shall be subject to an annual upward adjustment of three percent (3%) of the then-current Base
Rent during the initial Term. The first such adjustment shall become effective commencing on the first (1 st ) annual anniversary 
of the Phase 1 Premises Rent Commencement Date, and subsequent adjustments shall become effective on every successive
annual anniversary for the remainder of the initial Term of this Lease.

9. Operating Expenses .
     9.1. As used herein, the term “ Operating Expenses ” shall include:

				
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